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SunnyDays

ERA5 almanac — 8 years of real data

Atlanta in October

Atlanta in October: 25% of days see measurable rain, 73°F average high, 34% of days historically clear (n=248, ERA5 2018–2025).

Atlanta in October is historically a poor month for sun: only 34% of days clear across 8 years (n=248, avg high 73°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 Atlanta 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 October

Clear-sky percentage for Atlanta in October, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early October
1st–15th		 45% n=120 73°F
Late October
16th–end		 24% n=128 73°F
Full month average 34% n=248 73°F

Sunshine & warmth in October

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 Atlanta in October. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period Warm & sunny (≥72°F, >6 h sun) Sample (n)
Early October
1st–15th		 74% n=120
Late October
16th–end		 37% n=128
Full month average 55% n=248
10.8 h median sunshine per day 74% of days exceed 8 h sunshine 25% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 34%. Sunshine-based “warm & sunny”: 55%. The 21-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

Atlanta is mostly overcast in October historically: only 34% of days are clear across 8 years (n=248), avg high 73°F. The two halves differ materially (45% early, 24% late) — favour the early half of the month. Most visitors this month will see more clouds than sun.

Every month in Atlanta

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

Historical clear-sky % for Atlanta, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 0% n=248 All destinations →
February 2% n=226 All destinations →
March 11% n=248 All destinations →
April 24% n=240 All destinations →
May 32% n=248 All destinations →
June 26% n=240 All destinations →
July 15% n=248 All destinations →
August 20% n=248 All destinations →
September 40% n=240 All destinations →
October ← this page 34% n=248 All destinations →
November 6% n=240 All destinations →
December 1% n=248 All destinations →

Frequently asked

Does it rain in Atlanta in October?

Sometimes. Atlanta sees measurable rain on 25% of days in October historically (n=248 days, ERA5 2018–2025) — not frequent enough to plan around, but not negligible either.

Is Atlanta good for sun in October?

It's mixed. Atlanta in October is clear on 34% of days historically (avg high 73°F, n=248 days, ERA5 2018–2025) — the outcome varies year to year.

How Atlanta compares in October

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