ERA5 almanac comparison — 8 years of real data
Houston vs Puerto Rico: weather in September
Houston edges out Puerto Rico for sun in September: 30% clear historically versus 4% (8-year ERA5 average, a 26-point gap). Puerto Rico also sees measurably more rain than Houston this month (74% vs 50% of days). Both are viable — Houston is the safer bet.
Houston
TX
- Clear days, September
- 30%
- Sample size
- n=240 days
- Avg high
- 88°F
- Early September (1st–15th)
- 28%
- Late September (16th–end)
- 32%
- Rain frequency
- 50% of days
Puerto Rico
PR
- Clear days, September
- 4%
- Sample size
- n=240 days
- Avg high
- 87°F
- Early September (1st–15th)
- 4%
- Late September (16th–end)
- 5%
- Rain frequency
- 74% of days
Frequently asked
Is Houston or Puerto Rico warmer in September?
Houston runs warmer by day in September. Houston averages highs of 88°F (highs n=240 days); Puerto Rico averages highs of 87°F (highs n=240 days) (ERA5 2018–2025). Historical averages, not a forecast.
Does it rain more in Houston or Puerto Rico in September?
Puerto Rico is measurably wetter than Houston. Days with measurable rain: Houston 50%, Puerto Rico 74% (n=240 and n=240 days). ERA5 2018–2025; historical, not a forecast.
Which is sunnier in September, Houston or Puerto Rico?
Houston edges out Puerto Rico for sun in September: 30% clear historically versus 4% (8-year ERA5 average, a 26-point gap). Puerto Rico also sees measurably more rain than Houston this month (74% vs 50% of days). Both are viable — Houston is the safer bet.
Compare Houston vs Puerto Rico 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.