Last updated: March 2, 2024
The weather in Fullerton, United States, during January is characterized by an average temperature of -4°C (26°F). Highs can soar to 12°C (54°F), while lows may dip to -20°C (-4°F). Typically, the humidity level in Fullerton throughout January hovers around 73%.
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Average temperature
Maximum temperature
Humidity
In January, Fullerton averages 28 mm (1.1 inches) of rainfall, typically over the course of 4 rainy days. The month enjoys an average of 9 hours 33 minutes of daylight, with the sun shining for approximately 5 hours 6 minutes each day. Additionally, there is a 33% probability of sunny days during this period.
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Chance of sun
In January, the UV Index in Fullerton reaches a maximum of 3, indicating a level of Moderate exposure. The most intense UV radiation typically occurs between 12:00 and 14:00, during which unprotected skin may burn in as little as 30 minutes.
| 07:00 | 08:00 | 09:00 | 10:00 | 11:00 | 12:00 | 13:00 | 14:00 | 15:00 | 16:00 | 17:00 | 18:00 | 19:00 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UVI | 0 | 1 | 1 | 2 | 2 | 3 | 3 | 2 | 2 | 1 | 1 | 0 | 0 |
| Exposure | Low | Moderate | Low | ||||||||||
| Time to burn | 45 min | 30 min | 45 min | ||||||||||