About what weather
what weather is a free web app that compares today's temperature in your location with the temperature on the same calendar day in a past year, using historical weather records. It works anywhere in the world and requires no sign-up.
How it works
- Detects your location automatically (or defaults to a major city).
- Shows today's high and low temperature.
- Picks a past year — random by default, or choose any year back to 1960.
- Shows the high and low for that same day and place in that year, and the difference.
Where the data comes from
what weather's current and historical temperatures come from Open-Meteo, an open weather data service that aggregates observations from national meteorological archives. Its historical archive covers records reaching back to the middle of the 20th century for most parts of the world, which is what makes day-by-day comparisons across decades possible. The app queries this data live — it does not store, cache, or alter it.
Interesting facts
- Global average temperatures have risen measurably since the mid-20th century, according to long-term meteorological records — most of that warming has occurred since the 1970s.
- A daily "high" (maximum) temperature is typically recorded in the afternoon, while the daily "low" (minimum) usually occurs just before sunrise.
- The same calendar date can vary dramatically from year to year at the same location, because short-term weather systems sit on top of longer seasonal and climate patterns.
- Urban areas tend to record higher nighttime minimum temperatures than nearby rural areas — an effect known as the "urban heat island."
- Coastal cities usually show a narrower gap between daily high and low temperatures than inland cities, because large bodies of water moderate temperature swings.
- Long-running weather stations that have recorded temperatures continuously since the mid-20th century are what make day-by-day historical comparisons like this possible.
- Meteorologists distinguish "weather" (conditions on a specific day) from "climate" (long-term averages over decades) — comparing one day to one past day is a weather comparison, not a climate one.
- Many national weather services define a "heatwave" using a location-specific threshold and duration, rather than one fixed temperature for the whole world.
- Because Earth's seasons are reversed between hemispheres, the "same calendar day" can mean summer in one country and winter in another.
- Some of the world's longest continuous temperature records span more than a century, though most digitized, easily queryable historical archives — including the one this app uses, which reaches back to 1960 — cover several decades rather than the full record.
FAQ
Can I see what the weather was on this day last year?
Yes. what weather automatically compares today's forecasted high and low with the recorded high and low for the same calendar date one year ago (or any year you choose, back to 1960), for your current location or any location it detects.
How do I compare today's temperature with previous years?
Just open the app: it detects your location, shows today's temperature at the top, and a past year's temperature for the same date at the bottom. Tap the year in the bottom half to pick a specific year, step one year at a time with the arrows, or let it choose one at random.
How far back does the historical data go?
what weather can look up historical temperatures back to 1960, subject to data availability at your location. Some weather stations have shorter or incomplete records, in which case the app will tell you no data was found for that specific day and place.
Does what weather work outside my country?
Yes. The app works anywhere in the world with location and weather-archive coverage. It uses your device's location, or falls back to a default city if you decline, so there is no fixed list of supported countries — it is global by design.
Where does the temperature data come from?
Current and historical temperatures come from Open-Meteo, an open weather data service that aggregates records from national meteorological archives. what weather does not store or modify this data — it queries it live each time you open the app or change the comparison year.
Is what weather free?
Yes, completely. There is no sign-up, no account, no paywall, and no ads. It is a small, free utility built to answer one specific question quickly: how does today compare to a past year?
Why is today's temperature different from the same day years ago?
Day-to-day weather is shaped by short-term atmospheric patterns, not just the calendar date, so the same date can differ by many degrees from one year to the next. Longer-term shifts in average temperatures can also make certain years run warmer or cooler overall.