Across 3,868 round-trip routes worldwide, the single cheapest month to fly falls in September, October or November on 57% of them, while May, June or July is the most expensive month on 58%. The most common cheapest month is November (22% of routes); the most common priciest is June (22%). On the average route the cheapest month is 33% cheaper than the priciest, and on 17% of routes the gap is 50% or more.
A global study of 3,868 high-confidence round-trip routes across 69 origin cities and 85 destinations on six continents, from Flightmussy's own 12-month forward fare scans. The cheap window and the busy window are almost exactly inverted — the best time to fly is when most people have stopped looking. Free first-party data, free to republish with a link.
| Window | Cheapest month | Most expensive month |
|---|---|---|
| Single most common | November (22% of routes) | June (22% of routes) |
| Three-month cluster | Sep–Nov: 57% | May–Jul: 58% |
The 12 clean, high-coverage routes with the widest gap between their cheapest and most expensive month. On these, when you fly is a bigger lever than where you book.
| Route | Cheapest | Cheapest month | Priciest | Most expensive month | Swing |
|---|---|---|---|---|---|
| Auckland → Dubai | 1103 EUR | September 2026 | 25222 EUR | February 2027 | 96% |
| Nairobi → London | 697 EUR | September 2026 | 7923 EUR | April 2027 | 91% |
| Frankfurt → Cologne | 328 EUR | June 2026 | 3337 EUR | April 2027 | 90% |
| Beijing → Frankfurt | 620 EUR | October 2026 | 5095 EUR | January 2027 | 88% |
| Gothenburg → Milan | 41 EUR | August 2026 | 287 EUR | December 2026 | 86% |
| Kuala Lumpur → London | 615 EUR | February 2027 | 4341 EUR | October 2026 | 86% |
| Cologne → London | 34 EUR | July 2026 | 203 EUR | January 2027 | 83% |
| Milan → Paris | 35 EUR | July 2026 | 208 EUR | May 2027 | 83% |
| Bangkok → Kuala Lumpur | 112 EUR | October 2026 | 558 EUR | May 2027 | 80% |
| Barcelona → Seoul | 528 EUR | June 2026 | 2641 EUR | May 2027 | 80% |
| Beijing → Toronto | 962 EUR | September 2026 | 4812 EUR | April 2027 | 80% |
| Casablanca → Milan | 176 EUR | October 2026 | 882 EUR | May 2027 | 80% |
Round-trip fares from Flightmussy's live 12-month scans, last updated 2026-06-13. Prices change constantly — search live for current fares.
Figures are computed live over 3,868 round-trip routes priced in USD with at least 6 months of coverage and 20+ priced departure dates — the high-confidence subset of the full 5,211-route dataset. "Cheapest/priciest month" is the calendar month whose lowest observed fare was lowest/highest for that route. These are forward fare-scan observations, not live quotes or historical actuals. Free to quote or republish with a link to flightmussy.com. Open dataset: route_seo_data.json.
Flightmussy is a free flight meta-search built by one person in Oslo. No signup, no ads, no tracking — email is optional, only for route price alerts. Compare fares across airlines and see 12 months of prices at a glance — including low-cost carriers Google Flights often deprioritises (Widerøe, Wizz Air, Norwegian, Ryanair). Pay with a card at the airline, or use the Crypto button on any result to check out in BTC, ETH, USDT, BNB or AVA via Travala.
Flightmussy runs its own 12-month forward fare scans across thousands of routes worldwide and publishes the data openly. Read the cheapest month to fly almost anywhere → — a global study of when fares are lowest — or browse the cheapest destinations from a city: