Harrisburg, IL Weather Forecast
Saline County, Illinois
Seven-day outlook
39–79°F across the weekThe week runs between 52° and 79°, with today the warmest day of it. There is no real trend across it: one day looks much like the next. Sunday is the wettest day, peaking near 49%. 4 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 Harrisburg forecast
Harrisburg sits at 37.7377°N, 88.5458°W in Saline 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
- Saline County
- Coordinates
- 37.7377°N, 88.5458°W
- Population
- 7,907 · 2023 estimate
- Land area
- 6.612 sq mi
Place data from the US Census Bureau. Coordinates are the Census internal point for Harrisburg, 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 Harrisburg?
The nearest Doppler radar is KPAH (Paducah, KY), 48 miles to the SSW. 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 Harrisburg its center is about 3,400 ft above ground. That is comfortably inside the useful range. The lowest scan passes low enough over Harrisburg to show rotation in the part of a storm where tornadoes actually form.
The closest instrument actually measuring the air is KHSB · Harrisburg/Raleigh Arpt on the ASOS/AWOS network, 5.2 miles away. Near enough to be representative on most days, though a summer thunderstorm can soak one and miss the other entirely.
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 Harrisburg
- Eldorado, IL8 mi
- Marion, IL22 mi
- Johnston City, IL22 mi
- West Frankfort, IL24 mi
- McLeansboro, IL24 mi
- Herrin, IL27 mi
- Benton, IL28 mi
- Carterville, IL29 mi
Elsewhere in Illinois
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