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SunnyDays

ERA5 almanac — 8 years of real data

Aspen in August

Aspen in August: 26% of days see measurable rain, 78°F average high, 47% of days historically clear (n=248, ERA5 2018–2025).

Aspen in August is a mixed month for sun: 47% of days historically clear (n=248, avg high 78°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 Aspen 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 Aspen 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		 50% n=120 78°F
Late August
16th–end		 45% n=128 78°F
Full month average 47% n=248 78°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 Aspen 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		 98% n=120
Late August
16th–end		 85% n=128
Full month average 91% n=248
13.1 h median sunshine per day 98% of days exceed 8 h sunshine 26% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 47%. Sunshine-based “warm & sunny”: 91%. The 44-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

Aspen in August is genuinely mixed: 47% of days historically clear (n=248), avg high 78°F — roughly even odds. The outcome varies year to year; don't book if you need guaranteed sun.

Every month in Aspen

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

Historical clear-sky % for Aspen, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 0% n=248 All destinations →
February 0% n=226 All destinations →
March 0% n=248 All destinations →
April 0% n=240 All destinations →
May 3% n=248 All destinations →
June 34% n=240 All destinations →
July 43% n=248 All destinations →
August ← this page 47% n=248 All destinations →
September 39% n=240 All destinations →
October 2% n=248 All destinations →
November 0% n=240 All destinations →
December 0% n=248 All destinations →

Frequently asked

Does it rain in Aspen in August?

Sometimes. Aspen sees measurable rain on 26% of days in August historically (n=248 days, ERA5 2018–2025) — not frequent enough to plan around, but not negligible either.

Is Aspen good for sun in August?

It's mixed. Aspen in August is clear on 47% of days historically (avg high 78°F, n=248 days, ERA5 2018–2025) — the outcome varies year to year.

How Aspen compares in August

Head-to-head clear-sky comparisons against destinations travelers plausibly weigh against Aspen 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.