ERA5 almanac comparison — 8 years of real data
Nashville vs San Luis Obispo: weather in December
San Luis Obispo edges out Nashville for sun in December: 12% clear historically versus 0% (8-year ERA5 average, a 12-point gap). Both are viable — San Luis Obispo 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.
Nashville
TN
- Clear days, December
- 0%
- Sample size
- n=248 days
- Avg high
- 54°F
- Early December (1st–15th)
- 0%
- Late December (16th–end)
- 0%
- Rain frequency
- 33% of days
San Luis Obispo
CA
- Clear days, December
- 12%
- Sample size
- n=248 days
- Avg high
- 64°F
- Early December (1st–15th)
- 16%
- Late December (16th–end)
- 8%
- Rain frequency
- 25% of days
Compare Nashville vs San Luis Obispo 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.