Last updated: June 24, 2025
In Mountain View, United States, the average temperature in September hovers around 14°C (58°F). Expect potential extremes, with minimums plunging to -5°C (23°F) and maximums soaring to 32°C (90°F). Precipitation is quite modest, with about 29 mm (1.2 in) spread over 5 days, and the average humidity sits at a comfortable 46%.
In September in Mountain View, the average temperature is 14°C (58°F), with maximums reaching 32°C (90°F) and minimums dropping as low as -5°C (23°F). This diverse range in temperatures makes Mountain View an ideal destination for travelers seeking both warm and cool experiences during their visit.
In Mountain View in September, the precipitation amount is 29 mm (1.2 in) over a period of 5 days.
In Mountain View in September, humidity is 46%. With an average temperature of 14°C (58°F), this humidity feels like a refreshing yet slightly brisk breeze, making it quite pleasant for traveling as you can comfortably explore without feeling overheated.
In Mountain View in September, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in Mountain View.
UV Risk Categories
Weather in Mountain View varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Mountain View, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -6°C (22°F) | 30 mm (1.2 inches) | 91% | moderate |
| February Weather | -5°C (24°F) | 34 mm (1.3 inches) | 92% | high |
| March Weather | -1°C (31°F) | 67 mm (2.6 inches) | 84% | very high |
| April Weather | 4°C (39°F) | 50 mm (2.0 inches) | 74% | very high |
| May Weather | 9°C (49°F) | 67 mm (2.7 inches) | 62% | extreme |
| June Weather | 17°C (62°F) | 24 mm (0.9 inches) | 56% | extreme |
| July Weather | 21°C (70°F) | 15 mm (0.6 inches) | 44% | extreme |
| August Weather | 19°C (67°F) | 24 mm (0.9 inches) | 37% | extreme |
| September Weather | 14°C (58°F) | 29 mm (1.2 inches) | 46% | very high |
| October Weather | 5°C (42°F) | 30 mm (1.2 inches) | 67% | high |
| November Weather | 1°C (34°F) | 32 mm (1.2 inches) | 84% | moderate |
| December Weather | -5°C (23°F) | 31 mm (1.2 inches) | 88% | moderate |