ERA5 almanac — 8 years of real data

Portland in July

Portland in July: 38% of days see measurable rain, 80°F average high, 38% of days historically clear (n=248, ERA5 2018–2025).

Portland in July is historically a poor month for sun: only 38% of days clear across 8 years (n=248, avg high 80°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 Portland 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 July

Clear-sky percentage for Portland in July, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period	% Clear days	Sample (n)	Avg high
Early July 1st–15th	37%	n=120	80°F
Late July 16th–end	38%	n=128	80°F
Full month average	38%	n=248	80°F

Sunshine & warmth in July

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 Portland in July. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period	Warm & sunny (≥72°F, >6 h sun)	Sample (n)
Early July 1st–15th	76%	n=120
Late July 16th–end	85%	n=128
Full month average	81%	n=248

13.0 h median sunshine per day 80% of days exceed 8 h sunshine 38% of days see ≥ 1 mm rain — rain is not hidden

Comparison (old vs new): WMO-code “clear” bar: 38%. Sunshine-based “warm & sunny”: 81%. The 43-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

Portland is mostly overcast in July historically: only 38% of days are clear across 8 years (n=248), avg high 80°F. Most visitors this month will see more clouds than sun.

Every month in Portland

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

Historical clear-sky % for Portland, 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	2%	n=240	All destinations →
May	14%	n=248	All destinations →
June	27%	n=240	All destinations →
July ← this page	38%	n=248	All destinations →
August	39%	n=248	All destinations →
September	30%	n=240	All destinations →
October	7%	n=248	All destinations →
November	0%	n=240	All destinations →
December	0%	n=248	All destinations →

Frequently asked

Does it rain in Portland in July?

Sometimes. Portland sees measurable rain on 38% of days in July historically (n=248 days, ERA5 2018–2025) — not frequent enough to plan around, but not negligible either.

Is Portland good for sun in July?

It's mixed. Portland in July is clear on 38% of days historically (avg high 80°F, n=248 days, ERA5 2018–2025) — the outcome varies year to year.

How Portland compares in July

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

→ Portland vs Albany in July — Albany is 37% clear historically
→ Portland vs Boston in July — Boston is 37% clear historically
→ Portland vs Charlottesville in July — Charlottesville is 37% clear historically

→ Portland live forecast — this week’s actual 7-day weather, not historical
→ Best destinations in July — all destinations ranked by July 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.