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SunnyDays

ERA5 almanac — 8 years of real data

Wine Country Sonoma in April

Wine Country Sonoma in April is historically a poor month for sun: only 32% of days clear across 8 years (n=240, avg high 68°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 Wine Country Sonoma 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 April

Clear-sky percentage for Wine Country Sonoma in April, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early April
1st–15th		 21% n=120 68°F
Late April
16th–end		 44% n=120 68°F
Full month average 32% n=240 68°F

Bottom line

Wine Country Sonoma is mostly overcast in April historically: only 32% of days are clear across 8 years (n=240), avg high 68°F. The two halves differ materially (21% early, 44% late) — favour the late half of the month. Most visitors this month will see more clouds than sun.

Every month in Wine Country Sonoma

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

Historical clear-sky % for Wine Country Sonoma, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 1% n=248 All destinations →
February 8% n=226 All destinations →
March 8% n=248 All destinations →
April ← this page 32% n=240 All destinations →
May 61% n=248 All destinations →
June 90% n=240 All destinations →
July 96% n=248 All destinations →
August 95% n=248 All destinations →
September 86% n=240 All destinations →
October 68% n=248 All destinations →
November 16% n=240 All destinations →
December 0% 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.