Most Humid Cities in the United States
The ten most humid of America's major cities have a humidity level that averages over 72.5 percent year round.
New Orleans has the highest relative humidity among big US cities, with an average of nearly 86 percent. The Louisiana city is followed closely by second-ranked Jacksonville, Florida.
These numbers are annual averages based on humidity readings from 1961 to 1990.
The 56 major cities included in the weather rankings here represent the US urban areas with the most people, all those with over one million residents in 2020.
| City | Humidity |
|---|---|
| New Orleans, Louisiana | 75.9 |
| Jacksonville, Florida | 75.8 |
| Houston, Texas | 74.7 |
| Orlando, Florida | 74.1 |
| Tampa, Florida | 74.1 |
| San Francisco, California | 73.7 |
| Seattle, Washington | 73.3 |
| Miami, Florida | 73.2 |
| Portland, Oregon | 73.2 |
| Grand Rapids, Michigan | 72.7 |
| Rochester, New York | 72.6 |
Highest Morning Humidity
Relative humidity fluctuates throughout the day along with the air temperature. At the coolest time of day, humidity usually peaks. This is because cooler air holds less water, and relative humidity measures the percentage of water in the air compared to how much water the air can hold. The time of day when humidity levels are usually highest depends on the city and ranges from 4 am to 7 am local standard time.
The ten large cities that achieve the highest levels daily usually reach 84 to 90 percent humidity. Houston tops the list with an average peak of 89.7 % humidity at 6:00 am.
| City | Humidity | Time |
|---|---|---|
| Houston, Texas | 89.7 | 6 am |
| Jacksonville, Florida | 89.2 | 4 am |
| Orlando, Florida | 89.0 | 4 am |
| New Orleans, Louisiana | 87.6 | 6 am |
| Tampa, Florida | 87.5 | 7 am |
| Portland, Oregon | 84.8 | 4 am |
| Raleigh, North Carolina | 84.6 | 7 am |
| Nashville, Tennessee | 84.1 | 6 am |
| Birmingham, Alabama | 84.1 | 6 am |
| Miami, Florida | 83.9 | 7 am |
Highest Afternoon Humidity
When the temperature rises during the day, the humidity usually drops. For the ten most humid cities, the humidity never gets below 58.5 percent on average, even at its lowest point in the day. The list is topped by Milwaukee, where the humidity often stays at over 62 percent.
| City | Humidity | Time |
|---|---|---|
| Milwaukee, Wisconsin | 62.8 | noon |
| Buffalo, New York | 62.4 | 1 pm | Grand Rapids, Michigan | 62.0 | 1 pm |
| Seattle, Washington | 61.7 | 4 pm |
| Rochester, New York | 61.0 | 1 pm |
| Cleveland, Ohio | 61.0 | 1 pm |
| New Orleans, Louisiana | 60.7 | noon |
| Miami, Florida | 60.5 | 1 pm |
| San Francisco, California | 59.4 | 4 pm |
| Los Angeles, California | 58.7 | 4 pm |
| Portland, Oregon | 58.6 | 4 pm |
Reference
World Data Center for Meteorology. Climate of the World.