ERA5 almanac comparison — 8 years of real data
Charleston vs Houston: weather in May
Charleston edges out Houston for sun in May: 37% clear historically versus 23% (8-year ERA5 average, a 14-point gap). Houston also sees measurably more rain than Charleston this month (56% vs 40% of days). Both are viable — Charleston is the safer bet.
Charleston
SC
- Clear days, May
- 37%
- Sample size
- n=248 days
- Avg high
- 80°F
- Early May (1st–15th)
- 44%
- Late May (16th–end)
- 31%
- Rain frequency
- 40% of days
Houston
TX
- Clear days, May
- 23%
- Sample size
- n=248 days
- Avg high
- 85°F
- Early May (1st–15th)
- 29%
- Late May (16th–end)
- 17%
- Rain frequency
- 56% of days
Frequently asked
Is Charleston or Houston warmer in May?
Houston runs warmer by day in May. Charleston averages highs of 80°F (highs n=248 days); Houston averages highs of 85°F (highs n=248 days) (ERA5 2018–2025). Historical averages, not a forecast.
Does it rain more in Charleston or Houston in May?
Houston is measurably wetter than Charleston. Days with measurable rain: Charleston 40%, Houston 56% (n=248 and n=248 days). ERA5 2018–2025; historical, not a forecast.
Which is sunnier in May, Charleston or Houston?
Charleston edges out Houston for sun in May: 37% clear historically versus 23% (8-year ERA5 average, a 14-point gap). Houston also sees measurably more rain than Charleston this month (56% vs 40% of days). Both are viable — Charleston is the safer bet.
Compare Charleston vs Houston 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 forecast for any destination is on its own page and may differ from the long-run average. Data from Open-Meteo.