ERA5 almanac comparison — 8 years of real data
Houston vs Tucson: weather in December
Tucson edges out Houston for sun in December: 27% clear historically versus 6% (8-year ERA5 average, a 21-point gap). Houston also sees measurably more rain than Tucson this month (37% vs 13% of days). Both are viable — Tucson is the safer bet.
What you are reading: 8-year historical averages, not a forecast.
Either destination can still surprise you this specific December. For this
week’s actual forecast, each destination links to its live page below.
Houston
TX
- Clear days, December
- 6%
- Sample size
- n=248 days
- Avg high
- 67°F
- Early December (1st–15th)
- 5%
- Late December (16th–end)
- 6%
- Rain frequency
- 37% of days
Tucson
AZ
- Clear days, December
- 27%
- Sample size
- n=248 days
- Avg high
- 67°F
- Early December (1st–15th)
- 25%
- Late December (16th–end)
- 28%
- Rain frequency
- 13% of days
Compare Houston vs Tucson 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.