Glen Carbon, IL Weather Forecast
Madison County, Illinois
Sunrise and sunset
Next five days, scored 0 to 100The first day or two use the HRRR and NBM cloud layers. Later days only have total cloud, so treat them as a rough guide.
Know when sunset at this place will be worth a photo
We score every sunrise and sunset here from the cloud, haze and smoke forecast, and let you know when one is likely to light up. Sunrise the evening before, sunset a few hours ahead.
Seven-day outlook
34–68°F across the weekThe week runs between 34° and 68°, with Tuesday the warmest day of it. There is no real trend across it: one day looks much like the next. Every day in the outlook stays 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 Glen Carbon forecast
Glen Carbon sits at 38.7582°N, 89.9831°W in Madison 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
- Madison County
- Coordinates
- 38.7582°N, 89.9831°W
- Population
- 13,868 · 2023 estimate
- Land area
- 10.314 sq mi
Place data from the US Census Bureau. Coordinates are the Census internal point for Glen Carbon, 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 Glen Carbon?
The nearest Doppler radar is KLSX (St. Louis, MO), 38 miles to the W. 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 Glen Carbon its center is about 2,500 ft above ground. That is comfortably inside the useful range. The lowest scan passes low enough over Glen Carbon to show rotation in the part of a storm where tornadoes actually form. Glen Carbon is closer to its radar than 59% of US cities.
The closest instrument actually measuring the air is KALN · Alton/St Louis Rgnl on the ASOS/AWOS network, 9.5 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 Glen Carbon
- Maryville, IL2 mi
- Edwardsville, IL2 mi
- Pontoon Beach, IL5 mi
- Troy, IL6 mi
- Collinsville, IL6 mi
- Granite City, IL8 mi
- Madison, IL8 mi
- Wood River, IL9 mi
Elsewhere in Illinois
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