Weather WorldBig Mound, IL Weather Forecast
Quick Weather Clicks
Settings
Sun & Moon
Big Mound Weather Forecast
| OVERNIGHT | SUNDAY | SUNDAY NIGHT | MONDAY | MONDAY NIGHT | TUESDAY | WEDNESDAY | THURSDAY | THURSDAY NIGHT | FRIDAY | FRIDAY NIGHT | SATURDAY |
 |  |  | | | | | | |  | | |
| Mostly Clear | Mostly Sunny | Partly Cloudy | Mostly Sunny | Mostly Clear | Mostly Clear | Mostly Clear | Mostly Clear | Partly Cloudy | Partly Cloudy | Partly Cloudy | Partly Cloudy |
| Lo: 69°FLo: 21°C | Hi: 91°FHi: 33°C | Lo: 61°FLo: 16°C | Hi: 85°FHi: 29°C | Lo: 69°FLo: 21°C | Hi: 95°FHi: 35°C Lo: 71°FLo: 22°C | Hi: 95°FHi: 35°C Lo: 71°FLo: 22°C | Hi: 95°FHi: 35°C Lo: 71°FLo: 22°C | Hi: 91°FHi: 33°C Lo: 69°FLo: 21°C | Hi: 91°FHi: 33°C Lo: 69°FLo: 21°C | Hi: 89°FHi: 32°C Lo: 65°FLo: 18°C | Hi: 89°FHi: 32°C Lo: 65°FLo: 18°C |
POP = Probability of Precipitation.
Weather Outlook Updated: 127 AM CDT Sun Sep 13 2026 
Big Mound Radar Loop
Use the map search tool if you want to place a location marker on the radar map...
Big Mound Weather Map
Big Mound Quick Facts
Big Mound Forecast Discussion
Meteorlogic Glosserator
Instant definitions for any meteorological term.
Instant definitions for any meteorological term.
Issued: 1257 AM CDT Sun Sep 13 2026
Key Messages
- Very warm conditions with small rain chances in parts of southeast Missouri and north of Interstate 64 are forecast today and Monday.
- A major late season heat wave is forecast Tuesday through Thursday. High temperatures will reach the middle to upper 90s with daily peak heat index values around 105 degrees or higher. A Heat Advisory will very likely be needed.
- Slightly cooler and less humid conditions arrive by the end of the week, along with low-end 15 to 25% chances of thunderstorm...