ERA5 almanac comparison — 8 years of real data
Kiawah Island vs Tampa: weather in September
Kiawah Island edges out Tampa for sun in September: 33% clear historically versus 12% (8-year ERA5 average, a 21-point gap). Tampa also sees measurably more rain than Kiawah Island this month (67% vs 44% of days). Both are viable — Kiawah Island is the safer bet.
What you are reading: 8-year historical averages, not a forecast.
Either destination can still surprise you this specific September. For this
week’s actual forecast, each destination links to its live page below.
Kiawah Island
SC
- Clear days, September
- 33%
- Sample size
- n=240 days
- Avg high
- 83°F
- Early September (1st–15th)
- 29%
- Late September (16th–end)
- 37%
- Rain frequency
- 44% of days
Tampa
FL
- Clear days, September
- 12%
- Sample size
- n=240 days
- Avg high
- 87°F
- Early September (1st–15th)
- 6%
- Late September (16th–end)
- 18%
- Rain frequency
- 67% of days
Compare Kiawah Island vs Tampa in another month
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.