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SunnyDays

ERA5 almanac — 8 years of real data

Kiawah Island in July

Kiawah Island in July is historically a poor month for sun: only 7% of days clear across 8 years (n=248, avg high 87°F). October is the clearest month for Kiawah Island 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 Kiawah Island 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 July

Clear-sky percentage for Kiawah Island in July, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early July
1st–15th		 8% n=120 87°F
Late July
16th–end		 7% n=128 87°F
Full month average 7% n=248 87°F

Sunshine & warmth in July

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 Kiawah Island in July. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period Warm & sunny (≥72°F, >6 h sun) Sample (n)
Early July
1st–15th		 95% n=120
Late July
16th–end		 95% n=128
Full month average 95% n=248
12.5 h median sunshine per day 90% of days exceed 8 h sunshine 70% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 7%. Sunshine-based “warm & sunny”: 95%. The 88-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

Kiawah Island is a poor choice for sun in July: just 7% of days clear historically (n=248). October 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 October — historically the best month for sun in Kiawah Island.

Every month in Kiawah Island

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

Historical clear-sky % for Kiawah Island, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 1% n=248 All destinations →
February 6% n=226 All destinations →
March 14% n=248 All destinations →
April 41% n=240 All destinations →
May 38% n=248 All destinations →
June 22% n=240 All destinations →
July ← this page 7% n=248 All destinations →
August 10% n=248 All destinations →
September 33% n=240 All destinations →
October 46% n=248 All destinations →
November 14% n=240 All destinations →
December 4% 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.