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Average Relative Humidity
Key Weather Stations
Los Angeles County

Humidity, Weather

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"Relative humidity" (expressed as a percent) measures water vapor, but RELATIVE to the temperature of the air. In other words, it is a measure of the actual amount of water vapor in the air compared to the total amount of vapor that can exist in the air at its current temperature. As such, relative humidity by itself does not directly indicate the actual amount of water vapor present (definition from National Weather Service). Relative humidity is typically high near the coast, but may be quite low along the foothills. During periods of high temperatures, relative humidity is usually below normal so that discomfort is rare, except for those infrequent periods when high temperatures and high humidities occur simultaneously.

Monthly & Annual Averages - Over Period 2018-2022

DOWNTOWN LOS ANGELES (USC Campus)

Month Daily 4 A.M.* 10 A.M.* 4 P.M.* 10 P.M.*
January 57% 66% 43% 49% 66%
February 52% 63% 37% 44% 62%
March 61% 73% 46% 51% 70%
April 62% 74% 48% 53% 71%
May 66% 77% 54% 57% 74%
Month Daily 4 A.M.* 10 A.M.* 4 P.M.* 10 P.M.*
June 67% 79% 54% 58% 77%
July 68% 81% 52% 56% 78%
August 67% 81% 50% 55% 77%
September 67% 80% 49% 56% 78%
October 61% 72% 42% 53% 72%
Month Daily 4 A.M.* 10 A.M.* 4 P.M.* 10 P.M.*
November 58% 67% 41% 52% 70%
December 61% 70% 48% 55% 69%
Annual 62% 74% 47% 53% 72%

* Hour of day when measured.

LOS ANGELES INTERNATIONAL AIRPORT

Month Daily 4 A.M.* 10 A.M.* 4 P.M.* 10 P.M.*
January 61% 68% 48% 62% 66%
February 58% 65% 43% 56% 63%
March 66% 76% 54% 63% 71%
April 68% 77% 57% 64% 74%
May 72% 80% 63% 67% 77%
Month Daily 4 A.M.* 10 A.M.* 4 P.M.* 10 P.M.*
June 74% 82% 66% 70% 80%
July 77% 85% 67% 72% 83%
August 76% 85% 65% 70% 82%
September 73% 82% 62% 70% 79%
October 67% 75% 51% 67% 74%
Month Daily 4 A.M.* 10 A.M.* 4 P.M.* 10 P.M.*
November 62% 69% 45% 65% 69%
December 63% 69% 50% 64% 67%
Annual 68% 77% 56% 66% 74%

* Hour of day when measured.

LONG BEACH (Long Beach Airport)

Month Daily 4 A.M.* 10 A.M.* 4 P.M.* 10 P.M.*
January 65% 76% 51% 53% 75%
February 58% 72% 44% 45% 67%
March 64% 78% 52% 51% 73%
April 64% 79% 53% 51% 74%
May 68% 80% 59% 56% 75%
Month Daily 4 A.M.* 10 A.M.* 4 P.M.* 10 P.M.*
June 69% 81% 61% 56% 78%
July 68% 82% 59% 54% 77%
August 67% 82% 56% 53% 76%
September 67% 82% 55% 55% 76%
October 65% 79% 50% 54% 76%
Month Daily 4 A.M.* 10 A.M.* 4 P.M.* 10 P.M.*
November 61% 73% 45% 52% 72%
December 65% 76% 54% 56% 75%
Annual 65% 79% 53% 53% 75%

* Hour of day when measured.

Source: Western Regional Climate Center