ERA5 almanac comparison — 8 years of real data
Napa vs San Antonio: weather in April
Napa edges out San Antonio for sun in April: 42% clear historically versus 36% (8-year ERA5 average, a 6-point gap). San Antonio also sees measurably more rain than Napa this month (40% vs 14% of days). Both are viable — Napa is the safer bet.
What you are reading: 8-year historical averages, not a forecast.
Either destination can still surprise you this specific April. For this
week’s actual forecast, each destination links to its live page below.
Napa
CA
- Clear days, April
- 42%
- Sample size
- n=240 days
- Avg high
- 70°F
- Early April (1st–15th)
- 31%
- Late April (16th–end)
- 52%
- Rain frequency
- 14% of days
San Antonio
TX
- Clear days, April
- 36%
- Sample size
- n=240 days
- Avg high
- 82°F
- Early April (1st–15th)
- 40%
- Late April (16th–end)
- 33%
- Rain frequency
- 40% of days
Compare Napa vs San Antonio 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.