St Louis, Missouri weather in December

Averages from 2021–2025 (155 days of record).

Average high: 48°F
Average low: 32°F
Rainy days: ~8 per month
Total precipitation: 2.7 in
Warmest recorded: 74°F
Coldest recorded: -5°F

Expect December days in St Louis, Missouri to top out around 48°F and cool to about 32°F overnight, with roughly 8 days of measurable rain across the month. In recent years December has ranged from -5°F to 74°F.

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Current St Louis, Missouri forecast → · Historical data by Open-Meteo (ERA5).