September weather forecast
Los Alamos, NM

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Weather in September

September marks the beginning of fall in Los Alamos. The summer heat tapers off to give way to a cooler and cozier ambit. The city is decorated in hues of orange and brown as the telltale signs of autumn make an appearance. With the temperature dropping to 73.9°F (23.3°C), the city displays a kaleidoscope of warm fall colors. The peaceful charm of September offers a perfect retreat for natives and visitors alike.

Temperature

September witnesses a gentle descent in average high-temperature, descending from August's 79.7°F (26.5°C) to a still warm 73.9°F (23.3°C). September nights bring a significant cooling from the heat of the day, with averages of 51.6°F (10.9°C).

Humidity

The average relative humidity in September is 49%.

Rainfall

In Los Alamos, in September, it is raining for 11.7 days, with typically 1.22" (31mm) of accumulated precipitation. Throughout the year, there are 106.2 rainfall days, and 12.05" (306mm) of precipitation is accumulated.

Snowfall

June through September are months without snowfall in Los Alamos.

Daylight

In Los Alamos, the average length of the day in September is 12h and 23min.
On the first day of September, sunrise is at 6:37 am and sunset at 7:32 pm. On the last day of the month, sunrise is at 7:00 am and sunset at 6:49 pm MDT.

Sunshine

In Los Alamos, the average sunshine in September is 11.4h.

UV index

In Los Alamos, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for ordinary individuals.
Note: In September, the UV index of 4 transforms into the following advice:
Exercise prevention - Protecting skin and eyes from harm is required. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit.
Updated: Jul 31, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average September temperature?

Los Alamos in September has an average high-temperature of 73.9°F (23.3°C) and an average low-temperature of 51.6°F (10.9°C). In July, the average heat index (a.k.a. 'feels like', 'apparent temperature'), which combines relative humidity and air temperature, is appraised at 82.4°F (28°C).

What is the average humidity in September?

In Los Alamos, the average relative humidity in September is 49%.

How many days does it rain in September?

In Los Alamos, in September, during 11.7 rainfall days, 1.22" (31mm) of precipitation is typically accumulated.

When it does not snow?

June through September are months without snowfall.

Does it snow in September?

In Los Alamos, in September, it doesn't snow. In October, it regularly snows.

What is the average length of the day in September?

In September, the average day length is 12h and 23min.

When are sunrise and sunset in September?

On the first day of September, sunrise is at 6:37 am and sunset at 7:32 pm. On the last day of the month, sunrise is at 7:00 am and sunset at 6:49 pm MDT.

How many hours of sunshine does Los Alamos have in September?

The average sunshine duration in September in Los Alamos is 11.4h.

How high is the UV index in September?

The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate health threat from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Los Alamos, NM

Average temperature in September - Los Alamos, NM
  • Average high temperature in September: 73.9°F

The warmest month (with the highest average high temperature) is July (81.3°F).
The month with the lowest average high temperature is January (37.9°F).

  • Average low temperature in September: 51.6°F

The month with the highest average low temperature is July (59.2°F).
The coldest months (with the lowest average low temperature) are January and December (21.6°F).

Average pressure in September
Los Alamos, NM

Average pressure in September - Los Alamos, NM
  • Average pressure in September: 30.02"Hg

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

Average wind speed in September
Los Alamos, NM

Average wind speed in September - Los Alamos, NM
  • Average wind speed in September: 5.6mph

The windiest month (with the highest average wind speed) is April (8.1mph).
The calmest month (with the lowest average wind speed) is August (5.1mph).

Average humidity in September
Los Alamos, NM

Average humidity in September - Los Alamos, NM
  • Average humidity in September: 49%

The month with the highest relative humidity is January (70%).
The month with the lowest relative humidity is June (33%).

Average rainfall in September
Los Alamos, NM

Average rainfall in September - Los Alamos, NM
  • Average rainfall in September: 1.22"

The wettest month (with the highest rainfall) is July (2.56").
The driest month (with the least rainfall) is April (0.39").

Average rainfall days in September
Los Alamos, NM

Average rainfall days in September - Los Alamos, NM
  • Average rainfall days in September: 11.7 days

The month with the highest number of rainy days is July (18.2 days).
The month with the least rainy days is November (5.1 days).

Average snowfall in September
Los Alamos, NM

Average snowfall in September - Los Alamos, NM
  • Average snowfall in September: 0"

The month with the highest snowfall is January (5.24").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in September
Los Alamos, NM

Average snowfall days in September - Los Alamos, NM
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is December (8.1 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

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

The month with the longest days is June (Average daylight: 14h and 36min).
The month with the shortest days is December (Average daylight: 9h and 48min).

  • Average sunshine in September: 11h and 2min

The month with the most sunshine is June (Average sunshine: 12h and 6min).
The months with the least sunshine are January, February and December (Average sunshine: 7h and 6min).

Average sunshine days in September
Los Alamos, NM

Average sunshine days in September - Los Alamos, NM
  • Average sunshine days in September: 13.9 days

The month with the most sunshine days is November (22.8 days).
The month with the least sunshine days is July (8.9 days).

Average UV index in September
Los Alamos, NM

Average UV index in September - Los Alamos, NM
  • Average UV index in September: 4

The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in September
Los Alamos, NM

Average cloud cover in September - Los Alamos, NM
  • Average cloud cover in September: 12

The month with the most cloud cover is January (Cloud cover 22).
The month with the least cloud cover is June (Cloud cover 10).

Average visibility in September
Los Alamos, NM

Average visibility in September - Los Alamos, NM
  • 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, New Mexico, USA

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