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SunnyDays

ERA5 almanac — 8 years of real data

Crater Lake in August

Crater Lake in August: 15% of days see measurable rain, 73°F average high, 42% of days historically clear (n=248, ERA5 2018–2025).

Crater Lake in August is a mixed month for sun: 42% of days historically clear (n=248, avg high 73°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 Crater Lake 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 Crater Lake 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		 49% n=120 73°F
Late August
16th–end		 36% n=128 73°F
Full month average 42% n=248 73°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 Crater Lake 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		 67% n=120
Late August
16th–end		 52% n=128
Full month average 59% n=248
13.4 h median sunshine per day 98% of days exceed 8 h sunshine 15% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 42%. Sunshine-based “warm & sunny”: 59%. The 17-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

Crater Lake in August is genuinely mixed: 42% of days historically clear (n=248), avg high 73°F — more cloudy than clear. The outcome varies year to year; don't book if you need guaranteed sun.

Every month in Crater Lake

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

Historical clear-sky % for Crater Lake, 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 0% n=248 All destinations →
June 13% n=240 All destinations →
July 52% n=248 All destinations →
August ← this page 42% n=248 All destinations →
September 24% n=240 All destinations →
October 1% n=248 All destinations →
November 0% n=240 All destinations →
December 0% n=248 All destinations →

Frequently asked

Does it rain in Crater Lake in August?

Rarely. Only 15% of days in Crater Lake 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 Crater Lake good for sun in August?

It's mixed. Crater Lake in August is clear on 42% of days historically (avg high 73°F, n=248 days, ERA5 2018–2025) — the outcome varies year to year.

How Crater Lake compares in August

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