Dew point calculator
Check a reading from your own room
Have a thermometer and a hygrometer? The dew point calculator turns their two readings into a dew point, with the National Weather Service scale.
Open the dew point calculatorRankings
The most humid summers
Stations are ranked by the average dew point of June, July, and August, NOAA normals 1991–2020; each state by the median of its stations. The last column uses a 65°F basement.
Weather stations
top 15 of 445| Station | Summer dew point | Months above 60% |
|---|---|---|
| Corpus Christi Naval Air Station, TX | 75.9°F | 11 |
| Key West International Airport, FL | 75.0°F | 12 |
| Palacios Municipal Airport, TX | 74.9°F | 10 |
| Homestead Air Force Base, FL | 74.7°F | 12 |
| Brownsville, TX | 74.6°F | 12 |
| Corpus Christi, TX | 74.4°F | 10 |
| Tyndall Air Force Base, FL | 74.0°F | 9 |
| Port Arthur SE TX Airport, TX | 73.9°F | 9 |
| Miami Kendall Tamiami Executive Airport, FL | 73.8°F | 12 |
| St. Petersburg International Airport, FL | 73.7°F | 12 |
| Miami International Airport, FL | 73.7°F | 12 |
| Lake Charles, LA | 73.7°F | 9 |
| West Palm Beach International Airport, FL | 73.6°F | 12 |
| New Orleans Lakefront Airport, LA | 73.4°F | 9 |
| Melbourne International Airport, FL | 73.3°F | 12 |
States
all 50| State | Summer dew point | Stations |
|---|---|---|
| Florida | 73.0°F | 22 |
| Louisiana | 73.0°F | 7 |
| Mississippi | 70.2°F | 4 |
| Georgia | 69.9°F | 15 |
| Arkansas | 69.6°F | 7 |
| Alabama | 69.3°F | 8 |
| South Carolina | 69.2°F | 6 |
| North Carolina | 68.4°F | 11 |
| Texas | 68.3°F | 26 |
| Hawaii | 67.7°F | 6 |
| Tennessee | 67.2°F | 5 |
| Virginia | 66.2°F | 11 |
| Oklahoma | 66.1°F | 6 |
| Delaware | 65.7°F | 1 |
| Kentucky | 65.5°F | 8 |
| Missouri | 65.5°F | 9 |
| Maryland | 64.3°F | 3 |
| New Jersey | 63.7°F | 5 |
| Kansas | 63.2°F | 11 |
| Indiana | 63.0°F | 5 |
| Illinois | 62.8°F | 9 |
| Iowa | 62.5°F | 7 |
| West Virginia | 62.4°F | 7 |
| Ohio | 61.6°F | 11 |
| Nebraska | 61.6°F | 10 |
| Connecticut | 61.0°F | 2 |
| Rhode Island | 60.8°F | 1 |
| Pennsylvania | 60.3°F | 12 |
| Massachusetts | 59.6°F | 1 |
| Wisconsin | 59.0°F | 7 |
| New York | 59.0°F | 14 |
| Michigan | 58.8°F | 14 |
| South Dakota | 58.3°F | 8 |
| New Hampshire | 58.1°F | 3 |
| Minnesota | 57.8°F | 10 |
| Vermont | 56.8°F | 2 |
| Maine | 55.8°F | 4 |
| North Dakota | 55.3°F | 7 |
| California | 52.5°F | 29 |
| Washington | 48.6°F | 12 |
| New Mexico | 48.5°F | 8 |
| Oregon | 48.2°F | 13 |
| Alaska | 47.4°F | 22 |
| Colorado | 46.4°F | 13 |
| Montana | 45.2°F | 10 |
| Arizona | 42.8°F | 9 |
| Idaho | 41.8°F | 4 |
| Wyoming | 41.2°F | 8 |
| Utah | 38.8°F | 4 |
| Nevada | 33.9°F | 8 |
The driest summer is at Tonopah, NV, with a dew point of 30°F. Every state’s humid months, next to its running cost, are in our state study. Full citation of the NOAA data on Data sources.
Questions
Humidity questions
Short answers, with where they come from.
What is the dew point?
It’s the temperature at which the air would be saturated, and below which surfaces get wet. The higher it is, the more water the air holds. At Houston Intercontinental Airport, TX, the July normal is 73°F, its highest of the year.
NWS glossary, read Oct 5, 2026 · NOAA normalsWhy is my basement damp in summer?
Summer air holds more water. When it reaches a basement cooler than outside, it cools down and its relative humidity rises. When the basement is colder than the outdoor dew point, the air saturates and water forms on cool walls and pipes.
National Weather Service, vapor pressure formula, read Oct 5, 2026What humidity should a basement be?
The same as upstairs: below 60%, ideally between 30 and 50%. A dehumidifier set to that target cycles on and off by itself.
EPA, A Brief Guide to Mold, Moisture and Your Home, updated Feb 18, 2026How is this calculated?
We average NOAA’s hourly normal dew point for each month, then apply the National Weather Service vapor pressure formula at your basement’s temperature. A station is often an airport: your street can differ, and these are 30-year averages, not a forecast.
NOAA hourly normals 1991–2020 · National Weather Service, vapor pressure formula, read Oct 5, 2026