Last updated: March 2, 2024
The weather in Keystone, United States, during May is characterized by an average temperature of 2°C (35°F). Highs can soar to 13°C (56°F), while lows may dip to -10°C (15°F). Typically, the humidity level in Keystone throughout May hovers around 66%.
Minimum temperature
Average temperature
Maximum temperature
Humidity
In May, Keystone averages 81 mm (3.2 inches) of rainfall, typically over the course of 14 rainy days. The month enjoys an average of 14 hours 21 minutes of daylight, with the sun shining for approximately 11 hours 27 minutes each day. Additionally, there is a 42% probability of sunny days during this period.
Precipitation
Rainy days
Sunshine hours
Chance of sun
In May, the UV Index in Keystone reaches a maximum of 13, indicating a level of Extreme exposure. The most intense UV radiation typically occurs between 13:00 and 15:00, during which unprotected skin may burn in as little as 10 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 | 1 | 2 | 5 | 7 | 10 | 12 | 13 | 12 | 10 | 7 | 4 | 2 | 1 |
| Exposure | Low | Moderate | High | VeryHigh | Extreme | VeryHigh | High | Moderate | Low | ||||
| Time to burn | 45 min | 30 min | 25 min | 15 min | 10 min | 15 min | 25 min | 30 min | 45 min | ||||