September weather forecast and climate
Mammoth Lakes, CA

Perfect water reflections of trees, rocks, and distant mountains in the clear water of Mammoth Lakes, California
Perfect water reflections of trees, rocks, and distant mountains in the clear water of Mammoth Lakes, California

Weather in September

The first month of the autumn, September, is still a comfortable month in Mammoth Lakes, California, with temperature in the range of an average high of 65.8°F (18.8°C) and an average low of 41.5°F (5.3°C).

Temperature

In Mammoth Lakes, the average high-temperature marginally drops, from a pleasant 72.1°F (22.3°C) in August, to a comfortable 65.8°F (18.8°C). In Mammoth Lakes, California, the average low-temperature is 41.5°F (5.3°C).

Humidity

The average relative humidity in September is 38%.

Rainfall

In September, in Mammoth Lakes, the rain falls for 1.9 days. Throughout September, 0.12" (3mm) of precipitation is accumulated. In Mammoth Lakes, California, during the entire year, the rain falls for 47.7 days and collects up to 4.92" (125mm) of precipitation.

Snowfall

Months with snowfall are January through June, September through December. September is the first month it typically snows in Mammoth Lakes. Throughout September, in the average 0.7 snowfall days, it receives 0.12" (3mm) of snow. Throughout the year, in Mammoth Lakes, there are 60.8 snowfall days, and 28.58" (726mm) of snow is accumulated.

Daylight

In Mammoth Lakes, the average length of the day in September is 12.4h.

Sunshine

The average sunshine in September is 11h.

UV index

The average daily maximum UV index is 3. A UV Index value of 3 to 5 symbolizes a medium health hazard from the exposure to the Sun's UV radiation for average individuals.
Note: In September, the average maximum UV index of 3 translate into the following recommendations:
Take precautions - Protection against sunburn is recommended. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
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FAQ

What is the temperature in September in Mammoth Lakes?

The average high-temperature, in September, in Mammoth Lakes, California, is 65.8°F (18.8°C), while the average low-temperature is 41.5°F (5.3°C).

What is the average humidity in September in Mammoth Lakes?

The average relative humidity in September in Mammoth Lakes, California, is 38%.

How many days does it rain in September in Mammoth Lakes?

In Mammoth Lakes, in September, during 1.9 rainfall days, 0.12" (3mm) of precipitation is typically accumulated.

When does it start snowing in Mammoth Lakes?

September is the first month it typically snows in Mammoth Lakes. Throughout September, in the average 0.7 snowfall days, it receives 0.12" (3mm) of snow.

What is the average length of the day in September in Mammoth Lakes?

The average length of the day in September in Mammoth Lakes, California, is 12.4h.

How long on average sun shines in September in Mammoth Lakes?

The average sunshine in September in Mammoth Lakes is 11h.

What is the UV index reading in September in Mammoth Lakes?

In Mammoth Lakes, the average daily maximum UV index in September is 3. A UV Index value of 3 to 5 symbolizes a moderate health threat from unprotected exposure to the UV radiation.

Average temperature in September
Mammoth Lakes, CA

Average temperature in September - Mammoth Lakes, CA
  • Average high temperature in September: 65.8°F

The warmest month (with the highest average high temperature) is July (73.4°F).
The month with the lowest average high temperature is February (34°F).

  • Average low temperature in September: 41.5°F

The month with the highest average low temperature is July (48.2°F).
The coldest month (with the lowest average low temperature) is February (14.9°F).

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Average pressure in September
Mammoth Lakes, CA

Average pressure in September - Mammoth Lakes, CA
  • Average pressure in September: 29.93"

The month with the highest atmospheric pressure is January (30.16").
The month with the lowest atmospheric pressure is June (29.89").

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Average wind speed in September
Mammoth Lakes, CA

Average wind speed in September - Mammoth Lakes, CA
  • Average wind speed in September: 5.2mph

The windiest month (with the highest average wind speed) is March (6.9mph).
The calmest months (with the lowest average wind speed) are July and August (4.9mph).

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Average humidity in September
Mammoth Lakes, CA

Average humidity in September - Mammoth Lakes, CA
  • Average humidity in September: 38%

The month with the highest relative humidity is February (76%).
The month with the lowest relative humidity is August (34%).

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Average rainfall in September
Mammoth Lakes, CA

Average rainfall in September - Mammoth Lakes, CA
  • Average rainfall in September: 0.12"

The wettest month (with the highest rainfall) is February (0.94").
The driest months (with the least rainfall) are August and October (0.08").

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Average rainfall days in September
Mammoth Lakes, CA

Average rainfall days in September - Mammoth Lakes, CA
  • Average rainfall days in September: 1.9 days

The month with the highest number of rainy days is April (6.3 days).
The month with the least rainy days is August (1.8 days).

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Average snowfall in September
Mammoth Lakes, CA

Average snowfall in September - Mammoth Lakes, CA
  • Average snowfall in September: 0.12"

The month with the highest snowfall is February (5.67").
Months with the least snowfall are July and August (0").

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Average snowfall days in September
Mammoth Lakes, CA

Average snowfall days in September - Mammoth Lakes, CA
  • Average snowfall days in September: 0.7 days

The month with the highest number of snowfall days is March (11.3 days).
Months with the least snowfall days are July and August (0 days).

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Average daylight in September /
Average sunshine in September
Mammoth Lakes, CA

Average daylight in September / Average sunshine in September - Mammoth Lakes, CA
  • Average daylight in September: 12.4h

The month with the longest days is June (Average daylight: 14.7h).
The month with the shortest days is December (Average daylight: 9.6h).

  • Average sunshine in September: 11h

Months with the most sunshine are July and August (Average sunshine: 12h).
The month with the least sunshine is January (Average sunshine: 6.3h).

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Average sunshine days in September
Mammoth Lakes, CA

Average sunshine days in September - Mammoth Lakes, CA
  • Average sunshine days in September: 25.9 days

The month with the most sunshine days is October (27.3 days).
The month with the least sunshine days is March (18.2 days).

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Average UV index in September
Mammoth Lakes, CA

Average UV index in September - Mammoth Lakes, CA
  • Average UV index in September: 3

Months with the highest UV index are June and July (UV index 5).
Months with the lowest UV index are January, February, March, April, October, November and December (UV index 2).

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Average cloud cover in September
Mammoth Lakes, CA

Average cloud cover in September - Mammoth Lakes, CA
  • Average cloud cover in September: 8

The month with the most cloud cover is March (Cloud cover 30).
The month with the least cloud cover is August (Cloud cover 7).

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Average visibility in September
Mammoth Lakes, CA

Average visibility in September - Mammoth Lakes, CA
  • Average visibility in September: 6mi

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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