Last updated: June 24, 2025
In December, the average temperature in Joint Base Lewis McChord, United States hovers around 5°C (41°F), with extremes ranging from a chilly -8°C (17°F) to a milder 14°C (58°F). During this time, expect significant precipitation totaling 201 mm (7.9 in) over approximately 19 days, while humidity stays high at about 87%. Stay prepared for a blend of cold and wet conditions!
In December in Joint Base Lewis McChord, the average temperature is 5°C (41°F). Maximums can reach 14°C (58°F) and minimums can drop as low as -8°C (17°F). Be prepared for a mix of mild and chilly weather, making it essential to pack layers for your travels.
In Joint Base Lewis McChord in December, the total precipitation amount reaches 201 mm (7.9 in) over the course of 19 days.
In Joint Base Lewis McChord in December humidity is 87%. With an average temperature of 5°C (41°F), this humidity feels like a heavy, damp blanket enveloping you, making every step seem laborious and the chill more biting, which can be quite challenging for traveling.
In Joint Base Lewis McChord in December, the maximum UV index is 2, which corresponds to a low exposure category. With this level of UV radiation, the time to burn is approximately 45 minutes. To learn more about the hourly UV index in Joint Base Lewis McChord, you can visit Hourly UV Index in Joint Base Lewis McChord.
UV Risk Categories
Weather in Joint Base Lewis McChord varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Joint Base Lewis McChord, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 5°C (41°F) | 183 mm (7.2 inches) | 86% | low |
| February Weather | 4°C (40°F) | 189 mm (7.4 inches) | 84% | moderate |
| March Weather | 7°C (44°F) | 136 mm (5.4 inches) | 85% | moderate |
| April Weather | 9°C (49°F) | 118 mm (4.7 inches) | 83% | high |
| May Weather | 13°C (55°F) | 68 mm (2.7 inches) | 84% | very high |
| June Weather | 16°C (60°F) | 58 mm (2.3 inches) | 84% | very high |
| July Weather | 18°C (65°F) | 11 mm (0.4 inches) | 82% | very high |
| August Weather | 18°C (66°F) | 13 mm (0.5 inches) | 73% | very high |
| September Weather | 16°C (60°F) | 90 mm (3.5 inches) | 74% | high |
| October Weather | 10°C (51°F) | 142 mm (5.6 inches) | 83% | moderate |
| November Weather | 7°C (45°F) | 180 mm (7.1 inches) | 86% | moderate |
| December Weather | 5°C (41°F) | 201 mm (7.9 inches) | 87% | low |