Forecast, hour by hour
Temperature
For
The temperature ahead across the lower 48, Alaska, Hawaii and Puerto Rico, hour by hour, for seven days: warm and cold air on the move.
-20110 F
Forecast map / Forecast, each night
Forecast lows map
Over RAMSEY CANYON NEAR SIERRA VISTA, Arizona, where the map opens. The whole country
The lowest temperature of each night for the next seven days: frost, freeze, and warm nights that bring no relief. How to read it.
The rings are the storms the radars detect, the larger ring a severe one; each line runs to where its storm will be in an hour if it keeps its present speed and heading. Rotation and hail are what the radars detect and the analysis measures, not warnings: the official watches and warnings in force are drawn on the map in their own colours and set out in full under Alerts.
What the lows map shows
The lowest temperature of each night for the next seven days, the hours from 7 PM to 7 AM Eastern Standard Time. Where frost and freezing can reach, and where the night stays warm.
How to read it
- Below 0 F
- A bitter night.
- 0 to 32 F
- A freeze; pipes and plants at risk.
- 32 to 36 F
- Frost possible on clear, calm nights.
- 36 to 70 F
- A cool to mild night.
- Over 75 F
- A warm night that brings no relief from the heat.
What it is for
- See the first frost of autumn and the last of spring.
- Protect plants, pipes and animals before a freeze.
- Find the warm nights that make a heat wave dangerous.
How it is made
The forecast maps are drawn from the national blend of the forecast models: the models joined into one forecast and corrected against what each place has measured, on a grid 1.6 miles across, the forecast the country’s forecasters start from. Each of its main runs, four a day, is read whole, laid onto the same grid of latitude and longitude as the radar at 2.8 miles a cell, and played forward from now.
A frame each night for 7 days, played from tonight. As data: /radar/now.json?show=flo, the times of its frames.
In the Field Book
- Radiation budgetFB-ENG-007
Over a state
AlabamaAlaskaArizonaArkansasCaliforniaColoradoConnecticutDelawareDistrict of ColumbiaFloridaGeorgiaHawaiiIdahoIllinoisIndianaIowaKansasKentuckyLouisianaMaineMarylandMassachusettsMichiganMinnesotaMississippiMissouriMontanaNebraskaNevadaNew HampshireNew JerseyNew MexicoNew YorkNorth CarolinaNorth DakotaOhioOklahomaOregonPennsylvaniaRhode IslandSouth CarolinaSouth DakotaTennesseeTexasUtahVermontVirginiaWashingtonWest VirginiaWisconsinWyoming
With it
Severe AlertsWeather by stateForecast accuracyInstrument atlas
Beside it
Forecast, each day
Highs
For
The highest temperature of each day for the next seven days: where heat builds and where cold air holds.
-20110 F