ERA5 almanac — 8 years of real data

Seattle in June

Seattle in June: 28% of days see measurable rain, 71°F average high, 32% of days historically clear (n=240, ERA5 2018–2025).

Seattle in June is historically a poor month for sun: only 32% of days clear across 8 years (n=240, avg high 71°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 Seattle 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 June

Clear-sky percentage for Seattle in June, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period	% Clear days	Sample (n)	Avg high
Early June 1st–15th	21%	n=120	71°F
Late June 16th–end	42%	n=120	71°F
Full month average	32%	n=240	71°F

Sunshine & warmth in June

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 Seattle in June. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period	Warm & sunny (≥72°F, >6 h sun)	Sample (n)
Early June 1st–15th	22%	n=120
Late June 16th–end	49%	n=120
Full month average	36%	n=240

12.6 h median sunshine per day 78% of days exceed 8 h sunshine 28% of days see ≥ 1 mm rain — rain is not hidden

Comparison (old vs new): WMO-code “clear” bar: 32%. Sunshine-based “warm & sunny”: 36%.

Bottom line

Seattle is mostly overcast in June historically: only 32% of days are clear across 8 years (n=240), avg high 71°F. The two halves differ materially (21% early, 42% late) — favour the late half of the month. Most visitors this month will see more clouds than sun.

Every month in Seattle

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

Historical clear-sky % for Seattle, 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	1%	n=240	All destinations →
May	13%	n=248	All destinations →
June ← this page	32%	n=240	All destinations →
July	70%	n=248	All destinations →
August	61%	n=248	All destinations →
September	30%	n=240	All destinations →
October	3%	n=248	All destinations →
November	0%	n=240	All destinations →
December	0%	n=248	All destinations →

Frequently asked

Does it rain in Seattle in June?

Sometimes. Seattle sees measurable rain on 28% of days in June historically (n=240 days, ERA5 2018–2025) — not frequent enough to plan around, but not negligible either.

Is Seattle good for sun in June?

It's mixed. Seattle in June is clear on 32% of days historically (avg high 71°F, n=240 days, ERA5 2018–2025) — the outcome varies year to year.

How Seattle compares in June

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

→ Seattle vs Austin in June — Austin is 32% clear historically
→ Seattle vs Park City in June — Park City is 32% clear historically
→ Seattle vs Traverse City in June — Traverse City is 32% clear historically

→ Seattle live forecast — this week’s actual 7-day weather, not historical
→ Best destinations in June — all destinations ranked by June clear-sky %
→ All destinations
→ Raw data (JSON) — buckets, n, source

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.