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SunnyDays

ERA5 almanac — 8 years of real data

Denver in August

Denver in August: 22% of days see measurable rain, 89°F average high, 59% of days historically clear (n=248, ERA5 2018–2025).

Denver in August is a mixed month for sun: 59% of days historically clear (n=248, avg high 89°F). The outcome varies year to year — check the early/late split below. 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 August

Clear-sky percentage for Denver in August, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early August
1st–15th		 57% n=120 89°F
Late August
16th–end		 60% n=128 89°F
Full month average 59% n=248 89°F

Sunshine & warmth in August

A second measure using actual sunshine hours (ERA5 sunshine_duration), not the daily weather code. A Lowcountry day with 12 hours of sun and a 25-minute afternoon storm is counted below as a warm, sunny day — because it was. How we define this.

Sunshine-based metrics for Denver in August. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period Warm & sunny (≥72°F, >6 h sun) Sample (n)
Early August
1st–15th		 99% n=120
Late August
16th–end		 96% n=128
Full month average 97% n=248
12.7 h median sunshine per day 93% of days exceed 8 h sunshine 22% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 59%. Sunshine-based “warm & sunny”: 97%. The 38-point gap is from brief afternoon convective storms that stamp the whole day as “rain” in the WMO code but leave the bulk of the sunshine untouched.

Bottom line

Denver in August is genuinely mixed: 59% of days historically clear (n=248), avg high 89°F — more clear than cloudy. The outcome varies year to year; don't book if you need guaranteed 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 ← this page 59% n=248 All destinations →
September 74% n=240 All destinations →
October 38% n=248 All destinations →
November 6% n=240 All destinations →
December 1% n=248 All destinations →

Frequently asked

Does it rain in Denver in August?

Sometimes. Denver sees measurable rain on 22% of days in August historically (n=248 days, ERA5 2018–2025) — not frequent enough to plan around, but not negligible either.

Is Denver good for sun in August?

It's mixed. Denver in August is clear on 59% of days historically (avg high 89°F, n=248 days, ERA5 2018–2025) — the outcome varies year to year.

How Denver compares in August

Head-to-head clear-sky comparisons against destinations travelers plausibly weigh against Denver this month — same passport tier, similar flight distance, both sides from the same 8-year ERA5 record.

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.