Harrisburg, Illinois Weather
Cicadas claim the scorching afternoon. Day 14 of summer. Read this microseason across nine climate regions →
Harrisburg weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 4Overcast28%—92°69°—
- SundayJul 5Heavy Rain27%0.34″88°71°-4°
- MondayJul 6Overcast35%—88°72°0°
- TuesdayJul 7Overcast16%—84°69°-4°
- WednesdayJul 8Clear16%—89°66°+5°
- ThursdayJul 9Overcast23%—93°71°+4°
- FridayJul 10Thunderstorm43%0.50″87°72°-6°
AQI 57 (Moderate), driven by Ozone. AQI down 5 over the last 6 hours (gradual decline). Ozone at AQI 47 now. With UV 6.7 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 42 around 1 PM.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
Ozone × UV × Sky
Ozone at AQI 47 now. With UV 6.7 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 42 around 1 PM.
- Present
- AQI 47
- UV peak
- 6.7 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 42
PM × Wind × Precip
PM2.5 at 7.5 µg/m³ (AQI 42) with a 0.95 fine-to-coarse ratio and 3 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.95
- Wind
- calm
- Recent rain
- 0h in last 6h
- Pattern
- stagnant smoke
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
If the first of July be rainy weather, 'twill rain more or less for four weeks together.
- Moonrise
- 10:46 PM
- Moonset
- 10:03 AM
- In sign
- ♓︎ Pisces
Cicadas claim the scorching afternoon
Harrisburg at a glance
- Today vs. normal: 12°F above the seasonal normal for this latitude
- Last frost: April 2 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
ZIP code: 62946
16-Day Forecast — Harrisburg
- Sat92°69°28%
- Sun88°71°27%
- Mon88°72°35%
- Tue84°69°16%
- Wed89°66°16%
- Thu93°71°23%
- Fri87°72°43%
- Sat89°71°34%
- Sun79°65°13%
- Mon75°59°10%
- Tue79°61°8%
- Wed82°64°6%
- Thu84°65°16%
- Fri79°69°14%
- Sat83°71°26%
- Sun90°72°23%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of July 4, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.
SPC Convective Outlook
Storm Prediction Center — Harrisburg
SPC has placed Harrisburg in the Slight Risk category for severe thunderstorms today.
- TODAYSLGTSlight Risk
- TOMORROWTSTMGeneral Thunderstorms
- DAY 3TSTMGeneral Thunderstorms
Scattered severe storms possible. A few tornadoes, hail, and damaging wind gusts possible.
Source: NOAA / NWS Storm Prediction Center categorical convective outlook. Outlooks are re-issued multiple times per day; this page reflects the most recent SPC polygons covering the city’s coordinates.
ZIP codes in Harrisburg
- 62946