What's the cheapest day to fly in September?

We don't have enough real fare data for September to identify a cheapest weekday.

Is September a good time to visit Denver?

Check the real weather data above for Denver in September — we don't have crowd or event data to add beyond that.

Should I book now or wait?

There's no reliable way to predict whether a specific fare will rise or fall. If the real September fares above already fit your budget, booking removes the risk of the price changing.

Search Seattle → Denver in September

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Flights from Seattle to Denver in September

Planning a trip from Seattle to Denver in September? Find the best flights and seasonal tips. Flight time: 2h 26m.

Flying in September

Denver typically sees daytime highs around 28°C and overnight lows around 12°C in September, based on the last 3 years. Expect roughly 38 mm of rain across the month.