St. Charles, Iowa Weather
Prairie lightning bugs rise. Day 77 of spring. Read this microseason across nine climate regions →
St. Charles weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Heavy Rain44%0.40″83°65°—
- FridayJun 5Thunderstorm80%1.5″81°66°-2°
- SaturdayJun 6Showers80%0.14″85°64°+4°
- SundayJun 7Showers60%0.39″80°68°-5°
- MondayJun 8Light Showers56%0.03″80°68°0°
- TuesdayJun 9Thunderstorm29%—88°70°+8°
- WednesdayJun 10Thunderstorm12%—90°75°+2°
Ozone at AQI 31. AQI down 9 over the last 6 hours (steady decline since this morning). Overcast through the UV peak window (cloud cover ~100%) — afternoon ozone should stay flat.
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 31. Overcast through the UV peak window (cloud cover ~100%) — afternoon ozone should stay flat.
- Present
- AQI 31
- UV peak
- 3.3 at 1 PM
- Sky at peak
- overcast
- Projected peak
- AQI 7
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).
A summer fog for fair, a winter fog for rain.
- Moonrise
- 4:49 AM
- Moonset
- 2:13 PM
- In sign
- ♑︎ Capricorn
Prairie lightning bugs rise
St. Charles at a glance
- Today vs. normal: 7°F below the seasonal normal for this latitude
- Last frost: April 24 (climatological average for this latitude)
- Microseason: Jun 1–5
- Planting window: Harvest spring lettuce before it bolts. Sow heat-tolerant greens.
Right now in the garden
Peak growing season
As of June 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 — St. Charles
SPC has placed St. Charles in the Slight Risk category for severe thunderstorms tomorrow.
- TODAYMRGLMarginal Risk
- TOMORROWSLGTSlight Risk
- 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.