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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 2016-2020

DOWNTOWN LOS ANGELES (USC Campus)

Month Daily 4 A.M.* 10 A.M.* 4 P.M.* 10 P.M.*
January 62% 72% 49% 56% 71%
February 58% 67% 43% 50% 67%
March 63% 75% 47% 53% 72%
April 61% 73% 45% 52% 70%
May 67% 79% 55% 58% 76%
Month Daily 4 A.M.* 10 A.M.* 4 P.M.* 10 P.M.*
June 68% 79% 55% 58% 77%
July 67% 80% 51% 56% 77%
August 68% 81% 51% 57% 78%
September 65% 77% 47% 55% 75%
October 59% 70% 39% 51% 71%
Month Daily 4 A.M.* 10 A.M.* 4 P.M.* 10 P.M.*
November 58% 67% 41% 52% 70%
December 54% 63% 41% 48% 63%
Annual 63% 74% 47% 54% 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 66% 73% 55% 66% 70%
February 63% 68% 51% 61% 67%
March 69% 77% 57% 66% 73%
April 68% 78% 57% 65% 73%
May 73% 82% 64% 69% 79%
Month Daily 4 A.M.* 10 A.M.* 4 P.M.* 10 P.M.*
June 75% 83% 67% 70% 81%
July 76% 84% 66% 71% 83%
August 76% 85% 65% 72% 83%
September 72% 81% 61% 69% 78%
October 65% 73% 49% 64% 72%
Month Daily 4 A.M.* 10 A.M.* 4 P.M.* 10 P.M.*
November 63% 70% 45% 65% 70%
December 57% 62% 43% 58% 61%
Annual 69% 77% 57% 67% 75%

* 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 67% 78% 55% 57% 76%
February 63% 76% 50% 51% 71%
March 66% 80% 52% 52% 74%
April 64% 80% 53% 49% 73%
May 68% 81% 58% 56% 76%
Month Daily 4 A.M.* 10 A.M.* 4 P.M.* 10 P.M.*
June 69% 80% 61% 56% 77%
July 68% 81% 58% 54% 78%
August 69% 83% 58% 55% 79%
September 67% 81% 56% 56% 77%
October 65% 80% 49% 53% 77%
Month Daily 4 A.M.* 10 A.M.* 4 P.M.* 10 P.M.*
November 63% 75% 45% 54% 75%
December 60% 71% 47% 50% 69%
Annual 66% 79% 53% 54% 75%

* Hour of day when measured.

Source: Western Regional Climate Center