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SunnyDays

ERA5 almanac — 8 years of real data

Savannah in September

Savannah in September is historically a poor month for sun: only 32% of days clear across 8 years (n=240, avg high 85°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 Savannah 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 September

Clear-sky percentage for Savannah in September, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early September
1st–15th		 28% n=120 85°F
Late September
16th–end		 37% n=120 85°F
Full month average 32% n=240 85°F

Bottom line

Savannah is mostly overcast in September historically: only 32% of days are clear across 8 years (n=240), avg high 85°F. Most visitors this month will see more clouds than sun.

Every month in Savannah

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

Historical clear-sky % for Savannah, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 2% n=248 All destinations →
February 16% n=226 All destinations →
March 25% n=248 All destinations →
April 44% n=240 All destinations →
May 37% n=248 All destinations →
June 24% n=240 All destinations →
July 14% n=248 All destinations →
August 8% n=248 All destinations →
September ← this page 32% n=240 All destinations →
October 47% n=248 All destinations →
November 18% n=240 All destinations →
December 8% 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.