Alton, Missouri Weather
Cicadas claim the scorching afternoon. Day 14 of summer. Read this microseason across nine climate regions →
Alton weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 4Overcast13%—94°73°—
- SundayJul 5Heavy Drizzle24%0.09″91°72°-3°
- MondayJul 6Overcast31%—89°69°-2°
- TuesdayJul 7Overcast22%—91°66°+2°
- WednesdayJul 8Overcast——93°67°+2°
- ThursdayJul 9Mostly Clear21%—97°70°+4°
- FridayJul 10Overcast24%—88°77°-9°
AQI 39 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 8.5 µg/m³ (AQI 47) with a 0.96 fine-to-coarse ratio and 6 mph wind — combustion smoke trapped in calm air, not road dust.
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 36. Overcast through the UV peak window (cloud cover ~64%) — afternoon ozone should stay flat.
- Present
- AQI 36
- UV peak
- 7.4 at 1 PM
- Sky at peak
- overcast
- Projected peak
- AQI 18
PM × Wind × Precip
PM2.5 at 8.5 µg/m³ (AQI 47) with a 0.96 fine-to-coarse ratio and 6 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.96
- Wind
- light
- 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
- 10:55 PM
- Moonset
- 10:15 AM
- In sign
- ♓︎ Pisces
Cicadas claim the scorching afternoon
Alton at a glance
- Today vs. normal: 15°F above the seasonal normal for this latitude
- Last frost: March 27 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
ZIP code: 65606
16-Day Forecast — Alton
- Sat94°73°13%
- Sun91°72°24%
- Mon89°69°31%
- Tue91°66°22%
- Wed93°67°9%
- Thu97°70°21%
- Fri88°77°24%
- Sat83°69°20%
- Sun85°62°10%
- Mon85°61°7%
- Tue85°60°7%
- Wed87°63°15%
- Thu89°64°19%
- Fri91°69°13%
- Sat80°68°26%
- Sun79°68°22%
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 — Alton
SPC has placed Alton 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 Alton
- 65606