Weather World
City of Sullivan, IllinoisSullivan, IL Weather Forecast
Quick Weather Clicks
Settings
Sun & Moon
Sullivan Weather Forecast
| TONIGHT | MONDAY | MONDAY NIGHT | TUESDAY | TUESDAY NIGHT | WEDNESDAY | WEDNESDAY NIGHT | THURSDAY | THURSDAY NIGHT | FRIDAY | FRIDAY NIGHT | SATURDAY |
 |  |  |  |  |  |  |  | | | | |
| Mostly Cloudy | Mostly Sunny | Mostly Clear | Chance of T-Storm | Chance of T-Storm | Partly Cloudy | Partly Cloudy | Chance of Showers | Partly Cloudy | Partly Cloudy | Partly Cloudy | Mostly Sunny |
| Lo: 59°FLo: 15°C | Hi: 81°FHi: 27°C | Lo: 65°FLo: 18°C | Hi: 99°FHi: 37°C | Lo: 69°FLo: 21°C | Hi: 91°FHi: 33°C Lo: 71°FLo: 22°C | Hi: 91°FHi: 33°C Lo: 71°FLo: 22°C | Hi: 91°FHi: 33°C | Hi: 89°FHi: 32°C Lo: 69°FLo: 21°C | Hi: 89°FHi: 32°C Lo: 69°FLo: 21°C | Lo: 65°FLo: 18°C | Hi: 89°FHi: 32°C |
| POP: 50% | POP: 50% | POP: 30% |
POP = Probability of Precipitation.
Weather Outlook Updated: 337 PM CDT Sun Sep 13 2026 
Sullivan Radar Loop
Use the map search tool if you want to place a location marker on the radar map...
Sullivan Weather Map
Sullivan Quick Facts
Sullivan Forecast Discussion
Meteorlogic Glosserator
Instant definitions for any meteorological term.
Instant definitions for any meteorological term.
Issued: 150 PM CDT Sun Sep 13 2026
Key Messages
- Pleasant sleeping weather is expected tonight, with low temperatures in the 50s. Some lows near 50 can`t be ruled out in a few areas north of I-74.
- A significant temperature range is expected Tuesday through Thursday, based on placement of a stationary front. South of the front, highs in the mid 90s are likely, while low-mid 80s are more common north of it.
- Rainfall will be most widespread north of this front as well. Chances of more than an inch of rain range from 50-70% near Galesb...