June is the cheapest month to fly this route, with average fares around $154 round trip.
Average round-trip fares by departure month, based on current availability.
| Month | Avg Price | Lowest | Relative Cost | |
|---|---|---|---|---|
| May 2026 | $163 | $142 | ||
| June 2026 | $154 | $105 | Best | |
| July 2026 | $190 | $166 | Peak | |
| August 2026 | $187 | $166 |
Departing on Wednesday offers the lowest average fares at $157. Friday departures are the most expensive at $179, a difference of $22.
The best time to fly is June. Set up an alert and we'll notify you when prices drop.
Get Started Free →The cheapest month to fly from Denver to Seattle is June, with average round-trip fares around $154. The lowest fare found in June is $105.
Wednesday departures are the cheapest, averaging $157 round trip. The most expensive day is Friday at $179.
Based on current pricing trends, booking for June travel offers the best value. Avoid July if possible, as fares average $190 compared to $154 in the cheapest month. August is a solid middle-ground option at $187.
Flying in June instead of July can save you approximately $36 per round trip. The cheapest month averages $154 while the most expensive averages $190.
Airlines, flight times, price calendar, and more for Denver to Seattle
View DEN → SEA Details