Last updated: June 24, 2025
In September, the average temperature in Mountain View, United States is a pleasant 22°C (73°F). However, it can range from a cool 7°C (45°F) to a sweltering 35°C (95°F). Be prepared for some rain, as the region experiences approximately 126 mm (4.9 in) of precipitation over 11 days. With an average humidity of 75%, make sure to dress comfortably!
In September in Mountain View, the average temperature is 22°C (73°F). Maximums can reach 35°C (95°F) and minimums can be as low as 7°C (45°F). Be prepared for a warm climate with the possibility of cooler evenings, making it an ideal time to explore outdoor activities.
In Mountain View in September, the precipitation amount is 126 mm (4.9 in) over the course of 11 days.
In Mountain View in September humidity is 75%. With an average temperature of 22°C (73°F), this humidity feels like a warm, enveloping embrace, making it essential for travelers to stay hydrated and wear light, breathable clothing to enjoy their adventures comfortably.
In Mountain View in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For 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 | 5°C (41°F) | 87 mm (3.4 inches) | 86% | moderate |
| February Weather | 8°C (47°F) | 121 mm (4.8 inches) | 85% | high |
| March Weather | 11°C (52°F) | 97 mm (3.8 inches) | 84% | very high |
| April Weather | 15°C (60°F) | 119 mm (4.7 inches) | 82% | very high |
| May Weather | 20°C (69°F) | 124 mm (4.9 inches) | 83% | very high |
| June Weather | 24°C (75°F) | 93 mm (3.6 inches) | 82% | extreme |
| July Weather | 26°C (79°F) | 81 mm (3.2 inches) | 80% | extreme |
| August Weather | 25°C (77°F) | 114 mm (4.5 inches) | 74% | very high |
| September Weather | 22°C (73°F) | 126 mm (4.9 inches) | 75% | very high |
| October Weather | 17°C (63°F) | 120 mm (4.7 inches) | 79% | very high |
| November Weather | 9°C (49°F) | 87 mm (3.4 inches) | 87% | moderate |
| December Weather | 7°C (45°F) | 116 mm (4.6 inches) | 87% | moderate |