St. Louis · December
Run in the midday.
Cold: average high 47°F, low 31°F. Layering becomes the workout. Cold mornings warm into runnable midday hours — the windows around noon catch the warmest temperatures.
Avg high / low
47° / 31°F
Humidity
71%
Rain days
10/mo
Wind
12 mph
What December feels like in St. Louis
Sunrise
08:11
Mid-month average
Sunset
17:42
Mid-month average
Time-of-day breakdown
Morning
Coolest, driest air of the day. The window before sunrise is the most reliable comfortable hour.
Midday
Often the warmest few hours of a cold day. If you can only run once, midday gives you the most temperate window.
Evening
Cold drops back in fast after sunset. Tight window — done before headlamp territory.
What to wear running in St. Louis in December
The kit for December in St. Louis: cold-weather layers, gloves, and ear coverage on most mornings.
December vs the surrounding months
vs November
-8° avg high
0 rain days
St. Louis in November →
December
47°F avg high
10 rain days
Best: midday
vs January
+6° avg high
-1 rain days
St. Louis in January →
Frequently Asked Questions
What is the best time of day to run in St. Louis in December?+
Midday. Cold mornings warm into runnable midday hours — the windows around noon catch the warmest temperatures.
What's the average temperature in St. Louis in December?+
Average high 47°F, average low 31°F.
How does December compare to surrounding months in St. Louis?+
Compared to November (avg high 54°F), December is cooler. Compared to January (avg high 41°F), December is warmer.
Does it rain often in St. Louis in December?+
Expect about 10 measurable rain days in December, on average.