Humidity Today

Humidity Today reports two numbers side by side, because neither one tells the whole story on its own. Here is what each of them actually measures.

Relative humidity is the amount of water vapor in the air compared to how much the air can hold at its current temperature. Because warm air holds more moisture, the same RH number feels very different on a cool day versus a hot one — this is why “humid” at 50% in summer can feel far more uncomfortable than 50% in winter.

Dew point is the temperature at which the air becomes fully saturated. It is a more direct measure of how muggy the air feels: a dew point below 55°F generally feels dry, 55–65°F feels sticky, and above 65°F feels noticeably muggy. Tracking both figures together gives you a clearer picture of comfort than either one alone.

Why humidity peaks before sunrise, not at noon

The hourly curve above almost always looks the same shape, and the reason is temperature rather than rainfall. The absolute amount of water vapor sitting in the air changes slowly over a day, but the air's capacity to hold that vapor rises sharply as the sun heats the ground. Same moisture, bigger container — so the percentage falls through the morning, bottoms out in the middle of the afternoon when temperatures peak, then climbs again overnight as the air cools back toward its dew point.

That is why humidity readings are usually highest in the pre-dawn hours and why dew forms on grass at daybreak: the surface has cooled all the way down to that threshold and the air can no longer hold its moisture. If you are deciding when to run, walk a dog, or work outside, the low point on the curve in the late afternoon is typically the driest air of the day, even though it is also the hottest.

How humidity changes what the temperature feels like

Your body cools itself by evaporating sweat. When the air is already close to saturated, evaporation slows down and that cooling system loses most of its efficiency — so a humid 85°F afternoon can be genuinely more dangerous than a dry 95°F one. This is the mechanism behind the heat index, and it is why the “feels like” figure in the readout above can sit well above the actual air temperature on a muggy day.

The effect runs the other way in cold, dry air. Low humidity speeds up evaporation from your skin and airways, which is why winter air feels harsher than the thermometer suggests and why dry indoor heat tends to leave you with chapped lips, static shocks, and a scratchy throat.

What humidity level should you keep indoors?

Indoor comfort has a fairly narrow sweet spot. Most guidance puts it between 30% and 50% relative humidity: dry enough to keep mold, mildew, and dust mites in check, but damp enough to avoid the static, cracked furniture, and irritated sinuses that come with very dry air. Sustained readings above roughly 60% are where condensation and mold problems usually start, and readings below 30% are where dry-air complaints begin.

Outdoor humidity is the best early warning for both. When the outdoor figure climbs into the muggy range, a dehumidifier or air conditioner is doing real work to keep your indoor number down. When outdoor air is very cold and dry, heating it indoors drops that number further still, which is when a humidifier earns its keep. Checking the outdoor reading first tells you which direction you need to correct.

Everyday decisions humidity actually answers

Humidity is the number behind a surprising range of small questions: whether laundry on the line will actually dry, whether fresh paint or wood glue will cure on schedule, whether a hardwood floor or a guitar will move with the season, whether hair will hold a style, whether a workout should move indoors, and whether a musty basement needs a dehumidifier rather than a fan. In each case the useful reading is not just the current percentage but the direction it is heading over the next several hours — which is exactly what the hourly curve is for.

That is the whole point of checking Humidity Today before you commit to a plan: one number tells you how the air feels right now, and the curve beside it tells you whether waiting a few hours will help or hurt.

Every reading on Humidity Today comes from the Open-Meteo weather API, which aggregates open forecast and observation data published by national meteorological agencies — including NOAA in the United States and equivalent European and global models. We do not model the weather ourselves; we read the same numbers the forecasters publish and present the humidity slice of them without the clutter.

Values are requested for the coordinates of the city you searched and are refreshed hourly, with a short server-side cache of up to 30 minutes so the page stays fast under load. The timestamp above the readout shows the hour the current observation belongs to, in the local time zone of that city. The hourly curve blends the most recent observed hours with the forecast for the rest of the next 24 hours, which is why it can extend past the current time.

A note on accuracy: humidity varies more sharply over short distances than temperature does. A reading taken at a city's reference coordinates can differ from your own street by several points, especially near coastlines, lakes, irrigated land, or dense urban surfaces. Treat these numbers as a reliable picture of conditions in your area rather than a calibrated measurement at your exact address — for that you need a local hygrometer.

This site is an informational tool. It is not a substitute for official forecasts, warnings, or advisories, and it should not be used for aviation, marine, agricultural, medical, or any other safety-critical decision. For severe weather and heat advisories, always defer to your national weather service.