Skip to main content
SunnyDays

ERA5 almanac — 8 years of real data

Portland in June

Portland in June: 37% of days see measurable rain, 73°F average high, 27% of days historically clear (n=240, ERA5 2018–2025).

Portland in June is historically a poor month for sun: only 27% of days clear across 8 years (n=240, avg high 73°F). August is the clearest month for Portland historically. 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 June

Clear-sky percentage for Portland 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 73°F
Late June
16th–end		 33% n=120 73°F
Full month average 27% n=240 73°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 Portland 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		 44% n=120
Late June
16th–end		 62% n=120
Full month average 53% n=240
12.9 h median sunshine per day 76% of days exceed 8 h sunshine 37% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 27%. Sunshine-based “warm & sunny”: 53%. The 26-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 June historically: only 27% of days are clear across 8 years (n=240), avg high 73°F. If you want sun in Portland, August is historically much better. Most visitors this month will see more clouds than sun.

→ See all destinations in August — historically the best month for sun in Portland.

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 ← this page 27% n=240 All destinations →
July 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 June?

Sometimes. Portland sees measurable rain on 37% of days in June historically (n=240 days, ERA5 2018–2025) — not frequent enough to plan around, but not negligible either.

Is Portland good for sun in June?

Not usually. Portland is historically overcast in June: only 27% of days are clear (avg high 73°F, n=240 days, ERA5 2018–2025). August is historically far better for sun here.

How Portland compares in June

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.

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.