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SunnyDays

ERA5 almanac — 8 years of real data

Bozeman in August

Bozeman in August: 10% of days see measurable rain, 80°F average high, 67% of days historically clear (n=248, ERA5 2018–2025).

Bozeman in August is a mixed month for sun: 67% of days historically clear (n=248, avg high 80°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 Bozeman 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 Bozeman 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		 69% n=120 80°F
Late August
16th–end		 66% n=128 80°F
Full month average 67% n=248 80°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 Bozeman 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		 90% n=120
Late August
16th–end		 85% n=128
Full month average 87% n=248
13.2 h median sunshine per day 93% of days exceed 8 h sunshine 10% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 67%. Sunshine-based “warm & sunny”: 87%. The 20-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

Bozeman clears solidly in August: 67% of days historically (n=248), avg high 80°F. Most trips here in August will find more sun than cloud.

Every month in Bozeman

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

Historical clear-sky % for Bozeman, 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 8% n=248 All destinations →
June 38% n=240 All destinations →
July 72% n=248 All destinations →
August ← this page 67% n=248 All destinations →
September 48% n=240 All destinations →
October 5% n=248 All destinations →
November 0% n=240 All destinations →
December 0% n=248 All destinations →

Frequently asked

Does it rain in Bozeman in August?

Rarely. Only 10% of days in Bozeman see measurable rain in August, based on 8 years of ERA5 historical data (n=248 days, 2018–2025). This is a historical average, not a forecast.

Is Bozeman good for sun in August?

Yes. Bozeman is historically strong for sun in August: 67% of days are clear on average (avg high 80°F, n=248 days, ERA5 2018–2025).

How Bozeman compares in August

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