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SunnyDays

ERA5 almanac — 8 years of real data

Denver in October

Denver in October: rain frequency data not yet backfilled for this month, 68°F average high, 38% of days historically clear (n=248, ERA5 2018–2025).

Denver in October is historically a poor month for sun: only 38% of days clear across 8 years (n=248, avg high 68°F). Historical average, not a forecast.

What you are reading: 8-year historical averages from the ERA5 reanalysis, not a forecast. A month that is historically 90% clear can still be overcast on your specific trip. For this week’s actual forecast, see the live Denver page. Both can be true at once: “historically strong in this month; this particular week is not.” We label which is which.

Early vs. Late October

Clear-sky percentage for Denver in October, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early October
1st–15th		 48% n=120 68°F
Late October
16th–end		 28% n=128 68°F
Full month average 38% n=248 68°F

Bottom line

Denver is mostly overcast in October historically: only 38% of days are clear across 8 years (n=248), avg high 68°F. The two halves differ materially (48% early, 28% late) — favour the early half of the month. Most visitors this month will see more clouds than sun.

Every month in Denver

Compare across all months with data. Numbers are historical clear-sky %.

Historical clear-sky % for Denver, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 0% n=248 All destinations →
February 0% n=226 All destinations →
March 2% n=248 All destinations →
April 22% n=240 All destinations →
May 33% n=248 All destinations →
June 56% n=240 All destinations →
July 52% n=248 All destinations →
August 59% n=248 All destinations →
September 74% n=240 All destinations →
October ← this page 38% n=248 All destinations →
November 6% n=240 All destinations →
December 1% n=248 All destinations →

Frequently asked

Is Denver good for sun in October?

It's mixed. Denver in October is clear on 38% of days historically (avg high 68°F, n=248 days, ERA5 2018–2025) — the outcome varies year to year.

All percentages are historical averages from the ERA5 reanalysis via Open-Meteo, 8 full years (2018–2025). “Clear” means avg high ≥ 72 °F, precipitation < 1 mm, and a non-precipitation weather code. This is history, not a forecast. The live 7-day outlook for any destination is on its own page and may differ from the long-run average. Data from Open-Meteo.