Joliet, IL Weather Forecast
Will County, Illinois
Seven-day outlook
39–72°F across the weekThe week runs between 42° and 72°, with Tuesday the warmest day of it. There is no real trend across it: one day looks much like the next. Saturday is the wettest day, peaking near 69%. 3 of the 7 days stay dry.
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 Joliet forecast
Joliet sits at 41.5177°N, 88.1488°W in Will County, Illinois. 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
- Will County
- Coordinates
- 41.5177°N, 88.1488°W
- Population
- 150,489 · 2023 estimate
- Land area
- 66.123 sq mi
Place data from the US Census Bureau. Coordinates are the Census internal point for Joliet, 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 Joliet?
The nearest Doppler radar is KLOT (Chicago, IL), 6.8 miles to the NNE. 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 Joliet its center is about 340 ft above ground. That is about as close as radar coverage gets in the United States: the lowest scan is still near the ground when it reaches Joliet, so low-level rotation and the leading edge of a gust front show up on it. Joliet is closer to its radar than 98% of US cities.
The closest instrument actually measuring the air is KJOT · Joliet Rgnl on the ASOS/AWOS network, 1.6 miles away. Close enough that its readings are, for practical purposes, the conditions in town.
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 Illinois observing network as of this build.
Forecasts near Joliet
- Shorewood, IL3 mi
- Crest Hill, IL4 mi
- Lockport, IL8 mi
- Romeoville, IL8 mi
- Minooka, IL9 mi
- Channahon, IL9 mi
- Plainfield, IL9 mi
- New Lenox, IL9 mi
Elsewhere in Illinois
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