September weather forecast
Los Alamos, CA

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Weather in September

The first month of the autumn, September, is still a warm month in Los Alamos, California, with temperature in the range of an average high of 77.5°F (25.3°C) and an average low of 61.2°F (16.2°C).

Temperature

As Los Alamos steps into September, the average high-temperature holds at a still moderately hot 77.5°F (25.3°C), hinting at a minor fluctuation from the prior month. Nighttime temperature in Los Alamos experiences an average drop to a comfortable 61.2°F (16.2°C) in September.

Humidity

In September, the average relative humidity is 59%.

Rainfall

In Los Alamos, during September, the rain falls for 1.6 days and regularly aggregates up to 0.08" (2mm) of precipitation. In Los Alamos, during the entire year, the rain falls for 37.7 days and collects up to 5.98" (152mm) of precipitation.

Daylight

In Los Alamos, California, the average length of the day in September is 12h and 23min.
On the first day of September in Los Alamos, sunrise is at 6:34 am and sunset at 7:27 pm. On the last day of the month, sunrise is at 6:55 am and sunset at 6:45 pm PDT.

Sunshine

The average sunshine in September is 11.3h.

UV index

In Los Alamos, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for ordinary individuals.
Note: In September, the maximum UV index of 5 suggests this advice:
Take necessary precautions - Protection from skin and eye injury is mandatory. Protect yourself from the midday Sun's peak UV radiation by minimizing exposure. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly.
Updated: Aug 15, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the temperatures in September?

An average high-temperature, in September, in Los Alamos, is 77.5°F (25.3°C) and the average low-temperature is 61.2°F (16.2°C).

What is the average humidity in September?

In Los Alamos, the average relative humidity in September is 59%.

How many days does it rain in September in Los Alamos?

In Los Alamos, California, in September, during 1.6 rainfall days, 0.08" (2mm) of precipitation is typically accumulated.

What is the average length of the day in September?

The average day length in September is 12h and 23min.

When is the sunrise / sunset in September?

In September, on the first day of the month, sunrise is at 6:34 am and sunset at 7:27 pm. On the last day of the month, sunrise is at 6:55 am and sunset at 6:45 pm PDT.

How long on average sun shines in September?

In Los Alamos, California, the average sunshine duration in September is 11.3h.

What is the UV index intensity in September?

The average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a moderate health threat from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Los Alamos, CA

Average temperature in September - Los Alamos, CA
  • Average high temperature in September: 77.5°F

The warmest month (with the highest average high temperature) is August (78.8°F).
The month with the lowest average high temperature is December (61.2°F).

  • Average low temperature in September: 61.2°F

The month with the highest average low temperature is September (61.2°F).
The coldest month (with the lowest average low temperature) is February (47.8°F).

Average pressure in September
Los Alamos, CA

Average pressure in September - Los Alamos, CA
  • Average pressure in September: 29.91"Hg

The month with the highest atmospheric pressure is January (30.11"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.91"Hg).

Average wind speed in September
Los Alamos, CA

Average wind speed in September - Los Alamos, CA
  • Average wind speed in September: 7.2mph

The windiest month (with the highest average wind speed) is May (8.9mph).
The calmest month (with the lowest average wind speed) is July (6.7mph).

Average humidity in September
Los Alamos, CA

Average humidity in September - Los Alamos, CA
  • Average humidity in September: 59%

The month with the highest relative humidity is March (67%).
The months with the lowest relative humidity are October and November (58%).

Average rainfall in September
Los Alamos, CA

Average rainfall in September - Los Alamos, CA
  • Average rainfall in September: 0.08"

The wettest month (with the highest rainfall) is January (1.38").
The driest month (with the least rainfall) is June (0.04").

Average rainfall days in September
Los Alamos, CA

Average rainfall days in September - Los Alamos, CA
  • Average rainfall days in September: 1.6 days

The month with the highest number of rainy days is March (6.2 days).
The month with the least rainy days is August (0.8 days).

Average daylight in September /
Average sunshine in September
Los Alamos, CA

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

The month with the longest days is June (Average daylight: 14h and 30min).
The month with the shortest days is December (Average daylight: 9h and 54min).

  • Average sunshine in September: 11h and 2min

The months with the most sunshine are June and July (Average sunshine: 12h and 0min).
The month with the least sunshine is February (Average sunshine: 6h and 36min).

Average sunshine days in September
Los Alamos, CA

Average sunshine days in September - Los Alamos, CA
  • Average sunshine days in September: 27.9 days

The month with the most sunshine days is August (29 days).
The month with the least sunshine days is February (22.3 days).

Average UV index in September
Los Alamos, CA

Average UV index in September - Los Alamos, CA
  • Average UV index in September: 5

The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 3).

Average cloud cover in September
Los Alamos, CA

Average cloud cover in September - Los Alamos, CA
  • Average cloud cover in September: 6

The month with the most cloud cover is March (Cloud cover 24).
The month with the least cloud cover is August (Cloud cover 5).

Average visibility in September
Los Alamos, CA

Average visibility in September - Los Alamos, 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).

Los Alamos, California, USA

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