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SunnyDays

ERA5 almanac — 8 years of real data

Jacksonville in June

Jacksonville in June is historically a poor month for sun: only 15% of days clear across 8 years (n=240, avg high 88°F). April is the clearest month for Jacksonville 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 Jacksonville 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 Jacksonville 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		 16% n=120 88°F
Late June
16th–end		 14% n=120 88°F
Full month average 15% n=240 88°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 Jacksonville 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		 92% n=120
Late June
16th–end		 97% n=120
Full month average 94% n=240
12.1 h median sunshine per day 90% of days exceed 8 h sunshine 68% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 15%. Sunshine-based “warm & sunny”: 94%. The 79-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

Jacksonville is a poor choice for sun in June: just 15% of days clear historically (n=240). April is the historically strongest month for sun here. The 8-year record is consistent — this is not a fluke bad stretch.

→ See all destinations in April — historically the best month for sun in Jacksonville.

Every month in Jacksonville

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

Historical clear-sky % for Jacksonville, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 9% n=248 All destinations →
February 27% n=226 All destinations →
March 37% n=248 All destinations →
April 48% n=240 All destinations →
May 41% n=248 All destinations →
June ← this page 15% n=240 All destinations →
July 8% n=248 All destinations →
August 7% n=248 All destinations →
September 22% n=240 All destinations →
October 33% n=248 All destinations →
November 24% n=240 All destinations →
December 16% n=248 All destinations →

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.