🌤 Weather & Environment
Forecasts, air quality, UV index, and more — 9 free tools available. No signup required.
Forecasts, air quality, UV index, sunrise and sunset, moon phase, elevation and the "feels like" calculations that turn temperature and humidity into something meaningful.
The forecast data comes from Open-Meteo, which aggregates the output of national meteorological agencies — NOAA, ECMWF, DWD, Météo-France and the UK Met Office among them. That is worth knowing generally: most consumer weather products are interfaces over the same small number of publicly funded models, and differ mainly in presentation.
Nothing here carries official watches, warnings or advisories. Those are issued by human forecasters at national agencies and are the authoritative source when conditions are dangerous.
Where to start
- Weather Forecast — Current conditions and a seven-day forecast, in Fahrenheit and miles per hour by default.
- Air Quality Index (AQI) & PM2.5 Checker — Reports both the US and European index for the same measurement, which frequently disagree.
- UV Index Checker — Today's peak alongside the current reading, and clear-sky UV so cloud effect is measurable.
- Heat Index & Real-Feel Calculator — The NOAA apparent-temperature formula with the danger thresholds.
- Moon Phase & Lunar Calendar Tracker — Computed phase and illumination for any date rather than a lookup table.
- Sunrise & Sunset Calculator — Solar times including the twilight phases photographers care about.
All weather & environment (9)
Weather Forecast
Weather lookup for any city worldwide: current conditions and a 7-day forecast from the national met...
Sunrise & Sunset Calculator
Find sunrise and sunset times for any location and date. Calculate day length and golden hour. Free ...
UV Index Checker
Check the current UV index for any location. Get sun protection recommendations based on UV levels. ...
Air Quality Index (AQI) & PM2.5 Checker
An air quality checker for any city: real-time US AQI with the PM2.5, PM10, ozone and nitrogen dioxi...
Moon Phase & Lunar Calendar Tracker
A moon phase tracker showing the current phase, illumination percentage, lunar age, and the exact co...
Altitude & Elevation Finder
Find the ground elevation and altitude in feet and meters for any city, landmark, or mountain peak w...
Heat Index & Real-Feel Calculator
A heat index calculator running the full NWS procedure, including the low-humidity and high-humidity...
Wind Chill Index & Frostbite Risk Calculator
A wind chill calculator using the 2001 NWS index, with frostbite times — and what wind chill is not:...
Dew Point, Wet Bulb & Psychrometrics Calculator
Get dew point, wet bulb, frost point and absolute humidity, the pressure dew point in ppm for compre...
A forecast describes a grid cell, not your street
Numerical weather models divide the atmosphere into cells — kilometers across for the best regional models, tens of kilometers for global ones — and produce one value per cell, assuming a single terrain height for all of it. Everything inside that cell receives the same forecast. This is why a forecast can be right for your area and wrong for your garden, particularly for temperature in hilly terrain and for showers, which are physically smaller than the grid. It is a limitation of the method, not a failure of the source.
Seven days is two useful days and five hints
Forecast skill decays with lead time because small errors in the measured starting state of the atmosphere grow rapidly. The first two days are genuinely reliable; three to five days give a good sense of the pattern; day seven is an indication rather than a statement about that day. A seven-day panel presents all seven with identical visual confidence, which is a design convention rather than a claim about accuracy — and precipitation decays faster than temperature.
An air quality index is a convention, not a measurement
The measurement is a pollutant concentration in micrograms per cubic meter. The index is a national scale mapped onto it, and different countries map it differently. The same air can be "Unhealthy for Sensitive Groups" on the US scale and "Moderate" on the European one, with neither being wrong — they encode different judgements about risk thresholds. Our checker shows both for this reason, because an index number quoted without its scale is close to meaningless.
UV, cloud and vitamin D
The UV index is computed for clear sky and adjusted for actual cloud cover, which makes the difference between the two a direct measure of how much protection cloud is providing — sometimes substantial, often far less than people assume, since thin cloud blocks little UV. The index also drives vitamin D synthesis, which has an awkward property: it requires UVB, so it effectively stops below an index of about 3, which in northern latitudes means large parts of the year produce none regardless of how long you spend outside.
Frequently asked questions
Where does the forecast data come from?
Open-Meteo, which aggregates model output from national meteorological agencies including NOAA, ECMWF, DWD, Météo-France and the UK Met Office. We add no modeling of our own.
Do you show severe weather warnings?
No. Watches, warnings and advisories are issued by national agencies and we do not carry them. For safety decisions use weather.gov or your own national meteorological service.
Why does your air quality figure differ from another site?
Almost certainly because it is using a different national index, or a different reference station. The underlying concentration is usually similar; the scale applied to it is not.
Do you need my location?
No. These tools take a city name or coordinates you type. We do not request location permission and do not set an advertising identifier to serve a forecast.
How accurate is the elevation figure?
It comes from the Copernicus 90-meter digital elevation model, which averages terrain over a 90-meter grid square. That is accurate in flat terrain and understates sharp peaks — the elevation tool states the size of that effect on its own page.