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SunnyDays

ERA5 almanac — 8 years of real data

Charlotte in August

Charlotte in August is historically a poor month for sun: only 23% of days clear across 8 years (n=248, avg high 87°F). September is the clearest month for Charlotte 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 Charlotte 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 Charlotte 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		 12% n=120 87°F
Late August
16th–end		 33% n=128 87°F
Full month average 23% n=248 87°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 Charlotte 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		 92% n=120
Late August
16th–end		 91% n=128
Full month average 91% n=248
12.1 h median sunshine per day 85% of days exceed 8 h sunshine 46% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 23%. Sunshine-based “warm & sunny”: 91%. The 68-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

Charlotte is mostly overcast in August historically: only 23% of days are clear across 8 years (n=248), avg high 87°F. The two halves differ materially (12% early, 33% late) — favour the late half of the month. If you want sun in Charlotte, September is historically much better. Most visitors this month will see more clouds than sun.

→ See all destinations in September — historically the best month for sun in Charlotte.

Every month in Charlotte

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

Historical clear-sky % for Charlotte, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 0% n=248 All destinations →
February 1% n=226 All destinations →
March 11% n=248 All destinations →
April 36% n=240 All destinations →
May 40% n=248 All destinations →
June 36% n=240 All destinations →
July 22% n=248 All destinations →
August ← this page 23% n=248 All destinations →
September 44% n=240 All destinations →
October 35% n=248 All destinations →
November 6% n=240 All destinations →
December 2% 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.