Boulder in December
4.7out of 10
Not the best time
Cold: highs around 3°C. Some rain: about 5 rainy days.
3°CAvg high
-9°CAvg low
5Rainy days (23 mm)
9:10 hDaylight
07:22Sunrise · 16:32 Sunset
Why this score
- Cold: highs around 3°C
- Some rain: about 5 rainy days
- Nights fall to about -9°C
What to wear and pack
- Winter coat, hat and scarf
- Gloves for freezing mornings
How reliable is the forecast?
Rainfall in December is fairly consistent from year to year (2.4 days). Averages cover 30 years (1991–2020). Individual days can differ a lot.
Year at a glance
Weather by month
| Month | Avg high | Avg low | Rainfall | Rainy days | Humidity | Sunshine | Score |
|---|---|---|---|---|---|---|---|
| January | 4°C | -9°C | 23 mm | 6 | – | – | 4.7 |
| February | 5°C | -9°C | 26 mm | 7 | – | – | 4.7 |
| March | 10°C | -5°C | 50 mm | 9 | – | – | 5.5 |
| April | 13°C | -1°C | 77 mm | 11 | – | – | 5.9 |
| May | 18°C | 3°C | 103 mm | 16 | – | – | 6.2 |
| June | 24°C | 8°C | 77 mm | 14 | – | – | 7.2 |
| July | 27°C | 12°C | 75 mm | 15 | – | – | 7.1 |
| August | 26°C | 11°C | 71 mm | 15 | – | – | 7.1 |
| September | 22°C | 7°C | 54 mm | 10 | – | – | 7.8 |
| October | 16°C | 1°C | 47 mm | 8 | – | – | 6.9 |
| November | 8°C | -5°C | 33 mm | 6 | – | – | 5.6 |
| December | 3°C | -9°C | 23 mm | 5 | – | – | 4.7 |
Frequently asked questions
How hot is Boulder in December?
Daytime highs average 3°C and nights about -9°C.
When is the best time to visit Boulder?
The best months are September, June.