St. Clair, Missouri Weather
Cicadas claim the scorching afternoon. Day 14 of summer. Read this microseason across nine climate regions →
St. Clair weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 4Overcast43%—94°75°—
- SundayJul 5Light Drizzle35%0.02″85°70°-9°
- MondayJul 6Overcast21%—90°69°+5°
- TuesdayJul 7Overcast——89°67°-1°
- WednesdayJul 8Overcast10%—94°66°+5°
- ThursdayJul 9Light Drizzle29%—100°74°+6°
- FridayJul 10Drizzle42%0.01″94°72°-6°
AQI 45 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 11.8 µg/m³, PM10 at 12.7 µg/m³ — typical background levels with no transport signature.
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 41 now. With UV 5.6 peaking around 1 PM under partly cloudy skies, surface ozone likely climbs to AQI 22 around 1 PM.
- Present
- AQI 41
- UV peak
- 5.6 at 1 PM
- Sky at peak
- partly cloudy
- Projected peak
- AQI 22
PM × Wind × Precip
PM2.5 at 11.8 µg/m³, PM10 at 12.7 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.93
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- background
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
- 10:56 PM
- Moonset
- 10:12 AM
- In sign
- ♓︎ Pisces
Cicadas claim the scorching afternoon
St. Clair at a glance
- Today vs. normal: 18°F above the seasonal normal for this latitude
- Last frost: April 6 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
16-Day Forecast — St. Clair
- Sat94°75°43%
- Sun85°70°35%
- Mon90°69°21%
- Tue89°67°9%
- Wed94°66°10%
- Thu100°74°29%
- Fri94°72°42%
- Sat88°72°21%
- Sun81°62°8%
- Mon81°57°8%
- Tue84°60°10%
- Wed83°63°13%
- Thu86°65°13%
- Fri80°67°10%
- Sat91°68°15%
- Sun90°72°16%
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 — St. Clair
SPC has placed St. Clair 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 St. Clair
- 63077