ERA5 almanac comparison — 8 years of real data
Marfa vs St. Augustine: weather in December
Essentially a tie in December: Marfa is 11% clear historically, St. Augustine is 13% clear (8-year ERA5 average) — within the noise. Avg high 62°F vs 67°F. St. Augustine also sees measurably more rain than Marfa this month (25% vs 6% of days). Pick based on flight time or price, not weather — the weather won't decide this one for you.
Marfa
TX
- Clear days, December
- 11%
- Sample size
- n=248 days
- Avg high
- 62°F
- Early December (1st–15th)
- 10%
- Late December (16th–end)
- 12%
- Rain frequency
- 6% of days
St. Augustine
FL
- Clear days, December
- 13%
- Sample size
- n=248 days
- Avg high
- 67°F
- Early December (1st–15th)
- 13%
- Late December (16th–end)
- 13%
- Rain frequency
- 25% of days
Compare Marfa vs St. Augustine 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.