The climate in Alta during September can be summarized as cool and reasonably dry.
September is in the fall / autumn in Alta and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a cool 10°C (50°F), whilst at night 3°C (37°F) is normal.
Daytime temperature | 9.8°C 49.6°F |
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Nightly temperature | 2.8°C 37°F |
Average temperature | 6.3°C 43.3°F |
Daily sunshine | 4 hrs |
Avg rainfall | 58 mm 2.3 ins |
Rainy days | 18 days |
Sea temperature | 9.4°C 48.9°F |
Humidity | 85% |
Windspeed | 10.1kph 6 mph |
On average September is the 5th wettest month of the year in Alta with around 58mm 2.3 inches of rain making it a reasonably dry time to visit. This rainfall is typically spread over 18 days, although this may vary considerably.
On the flip side this corresponds to an average of 4 hours of sunshine per day.
The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Alta in September 2025.
Best places to visit in September
Hottest month: | July | 16.3°C 61.3°F |
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Driest month: | May | 33mm 1.3ins |
Sunniest month: | May | 0hrs |
Coldest month: | January | -3.1°C 26.4°F |
Wettest month: | October | 71mm 2.8ins |