September weather forecast
Island Mountain, CA

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Weather in September

The first month of the autumn, September, is still a pleasant month in Island Mountain, California, with temperature in the range of an average high of 69.8°F (21°C) and an average low of 54.3°F (12.4°C).

Temperature

Island Mountain witnesses the warmest weather in September, with temperatures averaging a high of 69.8°F (21°C) and a low of 54.3°F (12.4°C).

Humidity

September is the least humid month in Island Mountain, with an average relative humidity of 72%.

Rainfall

In Island Mountain, during September, the rain falls for 3.5 days and regularly aggregates up to 0.47" (12mm) of precipitation. Throughout the year, in Island Mountain, California, there are 102.7 rainfall days, and 28.78" (731mm) of precipitation is accumulated.

Snowfall

January, March through December are months without snowfall.

Daylight

The average length of the day in September is 12h and 26min.
On the first day of September in Island Mountain, sunrise is at 6:42 am and sunset at 7:44 pm. On the last day of the month, sunrise is at 7:10 am and sunset at 6:57 pm PDT.

Sunshine

The average sunshine in September is 10.4h.

UV index

In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for the average person.
Note: The UV index of 4 during September translates into the following guidance:
Preventative actions are necessary - Recommendations to ward off sunburn are given. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense.
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Frequently asked questions

What time of the year is the hottest in Island Mountain?

September is the month when Island Mountain sees the average highest temperatures, with a high of 69.8°F (21°C) and a low of 54.3°F (12.4°C).

What is the temperature in September in Island Mountain?

In Island Mountain, in September, the average high-temperature is 69.8°F (21°C), and the average low-temperature is 54.3°F (12.4°C).

What is the least humid month in Island Mountain?

With an average relative humidity of 72%, September is the least humid month.

What is the average humidity in September in Island Mountain?

In Island Mountain, California, the average relative humidity in September is 72%.

How much does it rain in Island Mountain in September?

In Island Mountain, California, during September, the rain falls for 3.5 days and regularly aggregates up to 0.47" (12mm) of precipitation.

When it does not snow in Island Mountain?

In Island Mountain, snow does not fall in January, March through December.

How many hours of daylight does Island Mountain have in September?

The average day length in September is 12h and 26min.

What time are sunrise and sunset in September in Island Mountain?

In September, on the first day of the month, sunrise is at 6:42 am and sunset at 7:44 pm. On the last day of the month, in Island Mountain, California, sunrise is at 7:10 am and sunset at 6:57 pm PDT.

How long on average sun shines in September in Island Mountain?

The average sunshine duration in September in Island Mountain, California, is 10.4h.

What is the UV index reading in September in Island Mountain?

In Island Mountain, California, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a medium health risk from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Island Mountain, CA

Average temperature in September - Island Mountain, CA
  • Average high temperature in September: 69.8°F

The warmest month (with the highest average high temperature) is September (69.8°F).
The month with the lowest average high temperature is December (53.4°F).

  • Average low temperature in September: 54.3°F

The months with the highest average low temperature are July, August and September (54.3°F).
The coldest month (with the lowest average low temperature) is February (43.5°F).

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Average pressure in September
Island Mountain, CA

Average pressure in September - Island Mountain, CA
  • Average pressure in September: 29.95"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are August and September (29.95"Hg).

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Average wind speed in September
Island Mountain, CA

Average wind speed in September - Island Mountain, CA
  • Average wind speed in September: 8.1mph

The windiest month (with the highest average wind speed) is June (10.6mph).
The calmest months (with the lowest average wind speed) are January and August (7.8mph).

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Average humidity in September
Island Mountain, CA

Average humidity in September - Island Mountain, CA
  • Average humidity in September: 72%

The month with the highest relative humidity is March (81%).
The month with the lowest relative humidity is September (72%).

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Average rainfall in September
Island Mountain, CA

Average rainfall in September - Island Mountain, CA
  • Average rainfall in September: 0.47"

The wettest month (with the highest rainfall) is December (5.31").
The driest month (with the least rainfall) is July (0.08").

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Average rainfall days in September
Island Mountain, CA

Average rainfall days in September - Island Mountain, CA
  • Average rainfall days in September: 3.5 days

The month with the highest number of rainy days is March (16.4 days).
The month with the least rainy days is August (1.8 days).

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Average snowfall days in September
Island Mountain, CA

Average snowfall days in September - Island Mountain, CA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (0.1 days).
The months with the least snowfall days are January, March, April, May, June, July, August, September, October, November and December (0 days).

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Average daylight in September /
Average sunshine in September
Island Mountain, CA

Average daylight in September / Average sunshine in September - Island Mountain, CA
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in September: 10h and 2min

The months with the most sunshine are July and August (Average sunshine: 11h and 42min).
The month with the least sunshine is December (Average sunshine: 5h and 0min).

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Average sunshine days in September
Island Mountain, CA

Average sunshine days in September - Island Mountain, CA
  • Average sunshine days in September: 25.9 days

The month with the most sunshine days is July (28.4 days).
The month with the least sunshine days is March (13.1 days).

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Average UV index in September
Island Mountain, CA

Average UV index in September - Island Mountain, CA
  • Average UV index in September: 4

The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, March, November and December (UV index 3).

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Average cloud cover in September
Island Mountain, CA

Average cloud cover in September - Island Mountain, CA
  • Average cloud cover in September: 14

The month with the most cloud cover is March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 10).

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Average visibility in September
Island Mountain, CA

Average visibility in September - Island Mountain, CA
  • Average visibility in September: 6mi

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

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Island Mountain, California, USA

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