Jefferson, IA Weather Forecast
Greene County, Iowa
Seven-day outlook
40–67°F across the weekThe week runs between 45° and 67°, with Sunday the warmest day of it. There is no real trend across it: one day looks much like the next. Monday is the wettest day, peaking near 81%.
Forecasts come from the National Weather Service's own computer models, and current conditions from the nearest reporting weather station. Both are served through the weather API. A forecast is guidance, not a warning, and anything the Weather Service has actually issued is on the live map.
The written summaries on this page are generated from the forecast data above, not by a meteorologist. Each sentence is a reading of the same numbers you can see, and no forecaster has reviewed them.
About the Jefferson forecast
Jefferson sits at 42.0177°N, 94.3794°W in Greene County, Iowa. The forecast above is drawn for that point from the National Weather Service's own computer models: a seven-day outlook, and a finer-grained one covering the next eighteen hours where it reaches, and the radar and alert panels show what the Weather Service has out over the area right now.
- County
- Greene County
- Coordinates
- 42.0177°N, 94.3794°W
- Population
- 4,100 · 2023 estimate
- Land area
- 6.016 sq mi
Place data from the US Census Bureau. Coordinates are the Census internal point for Jefferson, and the forecast is for that location, not for every address inside the city limits, and a large city can have real weather differences from one side to the other.
How well can the network see Jefferson?
The nearest Doppler radar is KDMX (Des Moines, IA), 39 miles to the ESE. A WSR-88D's lowest routine scan sits half a degree above horizontal, and the earth curves away beneath it, so by the time that beam reaches Jefferson its center is about 2,600 ft above ground. That is comfortably inside the useful range. The lowest scan passes low enough over Jefferson to show rotation in the part of a storm where tornadoes actually form. Jefferson is closer to its radar than 57% of US cities.
The closest instrument actually measuring the air is KPRO · Perry Muni on the ASOS/AWOS network, 17 miles away. Far enough that "current conditions" for Jefferson is an educated reading of somewhere else, worth knowing before you plan around a single temperature.
Beam height is the standard 4/3-earth approximation for the 0.5° scan and assumes normal refraction; it is where the center of the beam is, not its edges, and unusual temperature profiles bend it. Radar siting from the NWS WSR-88D network, station positions from the Iowa observing network as of this build.
Forecasts near Jefferson
- Perry, IA19 mi
- Carroll, IA25 mi
- Boone, IA26 mi
- Madrid, IA30 mi
- Adel, IA34 mi
- Fort Dodge, IA36 mi
- Polk City, IA38 mi
- Grimes, IA38 mi
Elsewhere in Iowa
Des MoinesCedar RapidsDavenportSioux CityIowa CityAnkenyAll Iowa forecasts →