Average Relative Humidity in September at US Cities





The average humidity in September is listed here for the largest cities in the United States. The tables below give this month's daily averages along with morning and afternoon relative humidity levels.

Relative humidity measures the actual amount of moisture in the air as a percentage of the maximum amount of moisture the air can hold.

For each city, the Daily number gives the average of humidity readings taken every three hours throughout the day. Morning values are recorded between 4 and 6 am local standard time, when usually temperatures are coolest and humidity highest. Afternoon humidity percentages are readings taken between 3 and 5 pm local standard time, when normally the day's temperature peaks and relative humidity reaches its lowest point. All the figures are averages for the years 1961 to 1990.

Average Relative Humidity (%) in September
Daily CityMorn­ing After­noon
74 Atlanta, Georgia 87 57
68 Austin, Texas 86 49
71 Baltimore, Maryland 85 54
74 Birmingham, Alabama 88 55
72 Boston, Massachusetts 82 62
74 Buffalo, New York 85 60
73 Charlotte, North Carolina 87 55
71 Chicago, Illinois 85 55
73 Cincinnati, Ohio 86 54
74 Cleveland, Ohio 84 60
73 Columbus, Ohio 86 54
67 Dallas, Texas 85 48
50 Denver, Colorado 69 34
73 Detroit, Michigan 87 55
73 Hartford, Connecticut 88 55
77 Houston, Texas 93 57
74 Indianapolis, Indiana 89 54
Daily CityMorn­ing After­noon
81 Jacksonville, Florida 93 66
70 Kansas City, Missouri 86 53
25 Las Vegas, Nevada 34 17
74 Los Angeles, California 83 67
73 Louisville, Kentucky 86 55
71 Memphis, Tennessee 86 55
78 Miami, Florida 88 69
75 Milwaukee, Wisconsin 87 63
71 Minneapolis, Minnesota 85 54
74 Nashville, Tennessee 90 54
78 New Orleans, Louisiana 89 63
68 New York, New York 78 56
67 Oklahoma City, Oklahoma 83 49
79 Orlando, Florida 92 65
72 Philadelphia, Pennsylvania 85 55
36 Phoenix, Arizona 50 23
72 Pittsburgh, Pennsylvania 85 55
Daily CityMorn­ing After­noon
69 Portland, Oregon 86 48
73 Providence, Rhode Island 86 59
77 Raleigh, North Carolina 92 57
77 Richmond, Virginia 91 57
77 Rochester, New York 89 61
57 Sacramento, California 77 31
46 Salt Lake City, Utah 61 29
68 San Antonio, Texas 86 48
73 San Diego, California 80 65
72 San Francisco, California 83 58
73 Seattle, Washington 86 57
72 St. Louis, Missouri 89 53
78 Tampa, Florida 90 63
74 Virginia Beach, Virginia 85 62
70 Washington, DC 82 55
Reference

World Data Center for Meteorology. Climate of the World.

US City Humidity
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