ERA5 almanac comparison — 8 years of real data
Las Vegas vs Marfa: weather in September
Las Vegas edges out Marfa for sun in September: 92% clear historically versus 64% (8-year ERA5 average, a 28-point gap). Marfa also sees measurably more rain than Las Vegas this month (20% vs 3% of days). Both are viable — Las Vegas is the safer bet.
What you are reading: 8-year historical averages, not a forecast.
Either destination can still surprise you this specific September. For this
week’s actual forecast, each destination links to its live page below.
Las Vegas
NV
- Clear days, September
- 92%
- Sample size
- n=240 days
- Avg high
- 98°F
- Early September (1st–15th)
- 88%
- Late September (16th–end)
- 95%
- Rain frequency
- 3% of days
Marfa
TX
- Clear days, September
- 64%
- Sample size
- n=240 days
- Avg high
- 84°F
- Early September (1st–15th)
- 58%
- Late September (16th–end)
- 71%
- Rain frequency
- 20% of days
Compare Las Vegas vs Marfa 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.