The Ultimate Guide: Finding the Absolute Best & Cheapest Times to Fly in 2025

Every traveler shares a common quest: to find the best time to fly. Whether you're chasing the lowest possible airfare or aiming for the smoothest, least stressful journey, timing is everything. From popular myths about Tuesday flights to the real impact of holiday travel, conflicting advice can make planning overwhelming.

But what if you could base your travel decisions on actual data? At Flight Delay Predictor, we've crunched millions of flight searches (from Expedia data) and years of historical flight performance (from U.S. Bureau of Transportation Statistics data, 2015-2024) to bring you a definitive, data-backed guide. Our goal is to cut through the guesswork and show you what the data says about when to book and when to fly to secure the cheapest flights and the most enjoyable trips.

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TL;DR – Quick Rules for Cheap, On-Time Flights

Airlines operate on a complex system of yield management, constantly adjusting prices based on demand, capacity, and competition. Beyond price, the best time to fly also impacts your experience. Fewer crowds, better on-time performance, and even smoother air can make a significant difference. Here's a quick summary of our key findings:

• Best time to book domestic: 21-45 days out.
• Best time to book international: 60-90 days out.
• Cheapest day to fly: Tuesday (also least delayed).
• Cheapest month to fly: September, October, November (shoulder season).
• Best time of day to fly: Early morning (5-7 AM) for fewer delays and often lower fares.
• Holiday travel hack: Fly on the actual holiday (e.g., Christmas Day) for fewer delays.
• Avoid: Last-minute bookings, peak summer, and Sunday flights.

How are US Flight Prices Changing Over Time?

Before diving into the specifics of booking times and days, let's take a macro look at the U.S. flight market. Are the complaints about rising airfares justified, or are flights actually becoming more accessible over the long haul? Our analysis of average annual fares and passenger volumes from 1996 to 2024 sheds light on these long-term trends.

Route-Specific Price Trends

Beyond national averages, certain routes consistently command higher or lower prices. Understanding these patterns can help you choose your next destination or departure city more strategically. We've pinpointed the 10 most expensive and 10 cheapest major routes based on average fares from 2022.

Most Expensive U.S. Routes in 2022

Figure 2 reveals significant disparities in average flight costs across popular US routes. The most expensive routes are largely long-haul, cross-country flights connecting major metropolitan areas. For instance, the route between New York City and San Francisco averages $414, making it the most expensive, followed closely by Los Angeles to New York City at $410.67. These routes often connect financial, tech, and cultural hubs, where demand for direct, convenient travel remains high.

Cheapest U.S. Routes in 2022

Conversely, the cheapest flights in recent years are often shorter-haul routes, particularly within high-traffic corridors like California or those connecting to major leisure destinations. The Las Vegas-Los Angeles route is the most budget-friendly at an average of $130, demonstrating a stark price difference of over 3x compared to the most expensive routes. Other inexpensive options include intra-California flights (e.g., Sacramento-San Diego at $131, San Diego-San Francisco at $149) and routes to/from Las Vegas (e.g., Las Vegas-Phoenix at $149.67). These routes often benefit from intense competition among multiple airlines, including budget carriers.

Traveler Takeaway: Observing this chart helps travelers identify potential savings. If flying between major coastal hubs, expect higher prices for transcontinental journeys. For shorter hops or routes connecting to highly competitive markets like Las Vegas, you're likely to find more budget-friendly options. This highlights the importance of route-specific research in finding the best deals.

Routes with the Biggest Fare Increases

While some routes might be consistently expensive or cheap, the real question for long-term travelers is: which routes have seen the most dramatic price increases or decreases over the past decades? Understanding these shifts can reveal changing market dynamics, demand patterns, or airline strategies.

Figure 3 provides a fascinating look into the long-term changes in flight fares from 1996 to 2024, revealing significant shifts in specific markets.

Routes experiencing the "Most Increased" fares show remarkable growth, with some nominal prices more than doubling. The route from San Francisco to Seattle, WA, tops this list with a staggering +142.5% increase in average nominal fare over the decades. Other significant increases are seen on routes like Portland, OR-San Francisco (+137.84%) and Dallas/Fort Worth, TX-Houston, TX (+135.06%). Many of these routes are within the Western U.S. or regional connections, suggesting growing demand, perhaps reduced competition, or increased operational costs in these specific corridors over time.

Conversely, routes in the "Least Increased/Decreased" category present a compelling counter-narrative to the perception of ever-rising airfares. Many of these high-volume routes have actually seen their nominal average fares decrease over the past ~28 years. The most significant decrease is observed on the Houston, TX-New York City (Metropolitan Area) route, with a -33.33% reduction in nominal fare. Other major routes like Dallas/Fort Worth, TX-San Francisco, CA (-22.67%), and Charlotte, NC-New York City, NY (-22.61%) also show substantial nominal price drops. This trend on major, competitive routes likely reflects sustained strong competition, increased airline efficiency, and perhaps the expansion of budget airlines on these popular corridors.

This analysis underscores the dynamic nature of air travel pricing. While some niche or regional routes have become significantly more expensive in nominal terms, many major cross-country and inter-city routes have defied inflation and actually become cheaper in nominal dollars over decades. It offers a historical context that can inform future travel planning, highlighting that not all flights are becoming more expensive; many have become more accessible.

How Far in Advance to Book Tickets

One of the most persistent questions in travel is: how far in advance to book a flight? Is it days ahead, or a few weeks? Our comprehensive analysis of Expedia flight search data provides clarity on the optimal booking window to find the cheapest flights.

We've analyzed millions of fare quotes across various routes to reveal the average price trends relative to the flight date. This gives you a powerful insight into when to book flights to maximize your savings.

As Figure 4 clearly illustrates, the price of a flight isn't linear; it follows a predictable curve within the 60-day window leading up to departure. The key takeaway for how far in advance to book a flight is that securing tickets closer to departure often comes at a significant premium.

Our data shows that flights booked just one day before departure have the highest average fare at approximately $387.71. Prices generally decrease as you book further out. A noticeable drop occurs within the first two weeks, where fares fall to around $339-$352.

Domestic Sweet Spot (21-45 Days)

The absolute lowest prices in this dataset typically appear when booking around 40 to 45 days in advance for domestic flights. For example, the lowest average fare is observed at 45 days out, at approximately $319.04. This period represents the "sweet spot" for finding the cheapest flights. Beyond this 45-day mark, as you look further out (e.g., towards 60 days in advance), the average fare shows a slight tendency to increase again, reaching around $330-$344. This suggests that while very last-minute is expensive, booking *too* far out within this 60-day window might also slightly increase your cost compared to the optimal 40-45 day window.

International Sweet Spot (60-90 Days)

While these averages apply broadly, international routes typically require booking even further in advance than 60 days to secure the very best deals, often falling into a 60-90 day window. Understanding this booking curve is your first step to finding cheap flights and avoiding unnecessary markups.

Holiday Travel: When to Avoid Airport Chaos

It's a common piece of advice: fly on the holiday itself to save money. But does the data back this up, and what about the often-dreaded holiday delays? We investigated millions of flight records around major U.S. holidays (from U.S. Bureau of Transportation Statistics data, 2015-2024).

Our in-depth analysis provides clear answers for holiday travel. As illustrated in Figures 5.1, 5.2, and 5.3, flying directly on the holiday itself often proves to be a strategic move for punctuality, and historically, for finding cheaper flights (though our current price data for holidays is pending).

Thanksgiving & Christmas Delay Patterns

Christmas Travel: A Clear Advantage on the Day

For Christmas travel, the data offers a compelling insight. The three days leading up to Christmas Eve (December 22nd-24th) are consistently among the most congested and delay-prone travel days of the year, with delay percentages hovering around 26.8% to 28.5%. However, our BTS data reveals that flying directly on Christmas Day (December 25th) dramatically drops the average delay rate to just 17.6%. That's a significant 9-11 percentage point improvement compared to the peak travel days immediately preceding it, making it the best time to fly for Christmas if avoiding delays is your priority.

Thanksgiving: Similar Trends

The pattern holds true for other major U.S. holidays. For Thanksgiving travel, the day before Thanksgiving is typically the busiest and most delayed, showing a 24.8% average delay rate. In contrast, flying on Thanksgiving Day sees this figure drop to 17.7%.

Summer Holidays (Memorial Day · 4 July · Labor Day)

Similarly, for Independence Day (July 4th) travel, the day before the holiday typically has a high delay rate of 27.5%, which plummets to a much more manageable 16.5% on July 4th itself.

This consistent trend across major holidays suggests that the reduced passenger volume on the actual holiday, combined with airports having a chance to clear out earlier disruptions, leads to a smoother travel experience.

Other Holidays: Less Dramatic, But Still Insights

While not always as dramatic as the Christmas, Thanksgiving, or Independence Day shifts, other holidays still present valuable insights:

• For New Year's Day, flights tend to have a slightly lower delay rate (e.g., ~19.3% in our data) compared to the days immediately preceding or following New Year's Eve, as peak inbound travel concludes.
• Holidays like Memorial Day and Labor Day generally see increased traffic on the Friday before and Monday after, pushing delay rates higher (e.S., ~20-22%) than regular weekdays, but without the significant "day-of" drop observed for the bigger holidays.
• Smaller holidays like Martin Luther King Jr. Day and Presidents' Day typically have less pronounced impacts on overall flight delays compared to a regular Monday, with slight increases on the Friday before and the holiday Monday itself.

This analysis helps you decide if a holiday flight could be your secret to finding a cheap time to fly during a busy period, without necessarily sacrificing punctuality.

Best Day of the Week to Fly

Beyond the time of year, the specific day of the week you choose to depart can significantly impact your fare and likelihood of delays. The long-standing wisdom says Tuesdays and Wednesdays are king, but does our extensive dataset agree?

Average Price by Day

Figure 6 reveals compelling trends in average flight prices throughout the week. Our analysis confirms that Tuesday is indeed the cheapest day of the week to fly, with an average total fare of approximately $297.04. This is closely followed by Wednesday at $303.70. This mid-week dip is a consistent pattern, making these days ideal for budget-conscious travelers.

Conversely, Sunday stands out as the most expensive day to fly, with an average fare of around $401.38. Friday also sees significantly higher prices at $360.07. This reflects increased demand for weekend travel and business trips.

On-Time Performance by Day

We dug into flight prices and on-time performance for every day of the week across our Expedia and BTS datasets to definitively answer: what is the best day to fly?

Our analysis of millions of flight records from the U.S. Bureau of Transportation Statistics (BTS) over nearly a decade confirms that the mid-week advantage for punctuality is very real. As illustrated in Figure 7, Tuesday and Wednesday consistently exhibit the lowest average delay percentages. For example, our data shows that flights on Tuesdays and Wednesdays are, on average, ~3-5% less likely to be delayed by 15 minutes or more compared to the weekend peaks.

Conversely, Friday and Sunday typically see the highest delay rates, as increased passenger volume and cascading disruptions from earlier in the week lead to more crowded skies and terminals.

Comparison of Price & Punctuality: When combining price and punctuality, Tuesday clearly emerges as the overall best day to fly. It offers both the lowest average fares and one of the lowest delay percentages. While Wednesday also presents a good option for both, the price advantage on Tuesday is often more pronounced. This insight is critical for those looking to maximize savings and minimize travel headaches. Understanding the weekly patterns allows you to strategically pick the best day of week to fly for your trip.

Cheapest Months to Fly in 2025

Beyond the day of the week, the month you choose to fly has a dramatic impact on prices. Seasonal demand, holidays, and school breaks all contribute to fluctuating fares throughout the year. Our data reveals the most and least expensive months to find the cheapest time of year to fly.

Why Shoulder Season Saves the Most

Figure 8 showcases the clear seasonal trends in average flight prices based on 2022 data. We observe that June is the most expensive month to fly, with an average total fare of approximately $400.16. This high cost is driven by peak summer vacation demand. May also shows elevated prices at $364.53, preceding the summer rush.

Conversely, the cheapest time of year to fly typically falls in the late fall. November stands out as the most budget-friendly month, with an average fare of about $266.88, closely followed by September at $300.61 and October at $304.24. These months benefit from reduced demand after the summer holidays and before the winter peak.

Insights for Travelers:

• Avoid Peak Summer (June-July) if budget is your main concern, unless your travel dates are absolutely fixed.
• Embrace Fall Travel (September-November) for significant savings and often pleasant weather, making it the best time of year to fly for value.
• Shoulder Seasons (April) can offer a balance, with prices around $354.53, being moderately higher than fall but much lower than peak summer.

Understanding these monthly variations allows for strategic planning, enabling you to choose the cheapest time to fly to your desired destination and maximize your travel budget.

Best Time of Day to Fly

Even within a single day, flight prices and on-time performance can vary. Many seasoned travelers swear by early morning flights, but is this just an old wives' tale, or is there data to support it?

Early-Morning vs. Evening Delays

We scrutinized departure times from our Expedia fare data and BTS delay records to uncover whether starting your journey at dawn truly offers benefits for finding the best time of day to fly.

Is setting that early alarm worth it? Our U.S. Bureau of Transportation Statistics (BTS) data reveals a clear pattern for punctuality. As seen in Figure 9, flights departing around 5 AM have the lowest average delay percentage at a remarkable 8.7%. This low rate extends into the early morning, with 6 AM at 9.2% and 7 AM at 11.7%. This makes the pre-8 AM window arguably the best time of day to fly for reliability and peace of mind, as airports are less congested and initial disruptions haven't yet cascaded.

Conversely, the worst time of day to fly in terms of delays often corresponds to the late afternoon and evening peaks. Our data shows delay percentages steadily climb throughout the day, reaching a peak around 8 PM (20:00) with an average delay rate of 29.6%. This is a staggering 20.9 percentage point difference compared to the 5 AM flights, highlighting just how significantly your departure hour can impact your journey's punctuality. These later hours often suffer from accumulated delays, weather issues, and increased air traffic, leading to a much higher chance of disruption.

While our direct data doesn't measure turbulence, general meteorological principles often suggest that the best time to fly to avoid turbulence is typically earlier in the morning. As the sun heats the ground, warm air rises, creating thermals that can lead to bumpier rides, especially over land. So, an early start can offer a smoother experience in more ways than one.

Fare Advantage by Departure Hour

Beyond on-time performance, choosing the right departure hour can also significantly impact your flight's cost. Our Expedia data (as depicted in Figure 10) reveals notable price fluctuations throughout the 24-hour cycle (all times in US Eastern Time):

As Figure 10 illustrates, the absolute cheapest time of day to fly is consistently around 5 AM, with an average fare of approximately $298.49. This early hour aligns perfectly with the lowest delay percentages (Figure 9), making it the optimal choice for both budget and punctuality.

Conversely, the most expensive time of day to fly is surprisingly at 3 AM, with an average fare soaring to about $462.90. This steep price is likely due to a very limited number of flights at this hour, primarily catering to niche, time-sensitive connections or repositioning flights, rather than general passenger demand. Flights around midnight (0 AM at $370.85) and in the immediate pre-dawn hours (1 AM at $416.39, 2 AM at $398.51) also remain notably high.

After the 5 AM low, prices generally climb through the late morning and early afternoon, reaching another relatively high point around 9 AM ($361.14) and 10 AM ($370.28). This period reflects the increased demand from business travelers and those preferring more "convenient" daytime departures.

Prices tend to drop again in the late evening, around 7 PM (19:00) to 8 PM (20:00), settling around $308-$314, which, while not as cheap as 5 AM, can still offer savings compared to mid-day flights.

The Takeaway: If you can brave the early alarm, the 5 AM to 7 AM window is your best bet for finding the cheapest flights and avoiding the most significant delays. These hours combine minimal congestion with lower demand for optimal value.

Best & Cheapest Time to Fly to Popular Destinations

While the general principles of finding the best time to fly and the cheapest time to fly apply broadly, specific destinations have their own unique seasonal demand, weather patterns, and event schedules. Here's how to apply these insights to popular routes:

Best Time to Fly to Hawaii

The allure of Hawaii is year-round, but prices and crowds fluctuate significantly. Our analyses show that the cheapest time of year to fly to Hawaii is often during the shoulder seasons. Specifically, late Spring (April-May) after Spring Break and before summer vacation, and Fall (September-November), after summer and before the Christmas rush, offer the best balance of affordability and pleasant weather. During these periods, average fares can be noticeably lower, and popular attractions are less crowded.

The most expensive times to visit Hawaii are predictably during peak travel seasons: late December through early January (for Christmas and New Year's), late February through March (for Spring Break), and the peak summer months (June-August). During these times, demand is at its highest, driving up airfares and hotel rates.

Beyond price, BTS data suggests that while these shoulder periods offer great value, even during peak times, early morning flights to Honolulu (HNL) and other major Hawaiian airports tend to have better on-time performance, minimizing travel headaches. For a more relaxed experience with fewer crowds and more available activities, aim for those shoulder seasons. Be aware that hurricane season runs from June to November, though direct hits are rare, it's worth monitoring forecasts if traveling in late summer/early fall.

Best Time to Fly to Japan

Japan's popularity has soared, making timing crucial for both price and experience. The cheapest time of year to fly to Japan generally falls outside the major peak seasons. This often includes late May-early June (after Golden Week and before the intense summer heat), and late October-November (post-autumn foliage peak, before winter). These periods can still offer pleasant weather with fewer tourist crowds and more accessible flight deals.

The most expensive and crowded times align with Japan's natural beauty and major holidays: late March-early April for the iconic cherry blossom season, late April-early May for Golden Week (a series of national holidays), and mid-October-early November for vibrant autumn foliage. Booking during these windows means paying a significant premium and navigating throngs of tourists at popular sites.

If budget is your absolute priority, consider traveling in January-February. While cold, it's the off-peak season, offering the lowest prices and a unique winter experience, especially in northern regions. The summer months (July-August) can also see lower prices due to extreme heat, humidity, and the start of typhoon season, but be prepared for challenging weather conditions.

Best Time to Fly to London / Europe

Europe remains a top destination, and like other popular regions, its flight prices are highly seasonal. The cheapest time of year to fly to Europe generally falls outside the bustling summer months (June-August). Your best bet for value is the spring shoulder season (March-May), which boasts milder weather, fewer crowds, and blossoming landscapes, or the fall shoulder season (September-October), offering comfortable temperatures, beautiful autumn colors, and the end of the peak tourist rush.

During the peak summer months (June-August), expect the highest fares and most crowded attractions, particularly in major cities like London, Paris, and Rome. Similarly, flights around Christmas and New Year's also see significant price increases due to holiday demand.

For the absolute cheapest flights to Europe, consider traveling in the off-peak winter months (November-February). While the weather can be cold and days are shorter, you'll find substantially lower fares, fewer tourists, and the opportunity to experience festive Christmas markets in many cities. Major events like Oktoberfest or specific city festivals can also create micro-peaks in demand, so check local calendars when planning.

For example, the best time to fly to Paris or the cheapest time to fly to London for a balance of good weather and lower prices is during these shoulder seasons, when prices are lower and crowds are thinner, offering a truly immersive experience.

Methodology & Data Sources

Our findings are based on a comprehensive analysis of millions of flight searches from Expedia data and years of historical flight performance from U.S. Bureau of Transportation Statistics (BTS) data, covering 2015-2024. This robust dataset allows us to provide accurate, data-backed insights on flight pricing trends, on-time performance, and optimal booking and travel times.

Navigating the complexities of airfare and flight schedules doesn't have to be a guessing game. By understanding the data behind flight pricing and on-time performance, you're empowered to make smarter travel decisions.

We've shown you the data on when is the best time to fly – from booking windows to the optimal days and times of day, and even seasonal variations for popular destinations. Whether your priority is securing the cheapest flights or ensuring a smooth, delay-free journey, the insights are clear: flexibility and strategic timing are your most valuable assets.

So, next time you're planning a trip, let the data guide you. A little bit of knowledge and proactive planning can go a long way in ensuring a more affordable, enjoyable, and punctual journey.

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