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SunnyDays

ERA5 almanac — 8 years of real data

Hartford in August

Hartford in August: 38% of days see measurable rain, 82°F average high, 40% of days historically clear (n=248, ERA5 2018–2025).

Hartford in August is a mixed month for sun: 40% of days historically clear (n=248, avg high 82°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 Hartford 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 Hartford 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		 38% n=120 82°F
Late August
16th–end		 41% n=128 82°F
Full month average 40% n=248 82°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 Hartford 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		 88% n=120
Late August
16th–end		 82% n=128
Full month average 85% n=248
12.5 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: 40%. Sunshine-based “warm & sunny”: 85%. The 45-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

Hartford in August is genuinely mixed: 40% of days historically clear (n=248), avg high 82°F — more cloudy than clear. The outcome varies year to year; don't book if you need guaranteed sun.

Every month in Hartford

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

Historical clear-sky % for Hartford, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 0% n=248 All destinations →
February 0% n=226 All destinations →
March 1% n=248 All destinations →
April 3% n=240 All destinations →
May 22% n=248 All destinations →
June 39% n=240 All destinations →
July 34% n=248 All destinations →
August ← this page 40% n=248 All destinations →
September 38% n=240 All destinations →
October 11% n=248 All destinations →
November 2% n=240 All destinations →
December 0% n=248 All destinations →

Frequently asked

Does it rain in Hartford in August?

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

Is Hartford good for sun in August?

It's mixed. Hartford in August is clear on 40% of days historically (avg high 82°F, n=248 days, ERA5 2018–2025) — the outcome varies year to year.

How Hartford compares in August

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