| NWS Forecast for: Ottawa IL Issued by: National Weather Service Chicago, IL Last Update: 4:31 am CDT Sep 15, 2026 |  |
Overnight: A 30 percent chance of showers and thunderstorms, mainly after 5am. Mostly cloudy, with a low around 19. South wind around 25 km/h, with gusts as high as 40 km/h. Tuesday: Showers and thunderstorms likely, mainly before 3pm. Partly sunny, with a high near 29. South wind 15 to 20 km/h becoming west in the afternoon. Winds could gust as high as 30 km/h. Chance of precipitation is 60%. New rainfall amounts between 1 and 2.5 mm, except higher amounts possible in thunderstorms. Tuesday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 11pm. Mostly cloudy, with a low around 18. North northwest wind around 10 km/h, with gusts as high as 20 km/h. Chance of precipitation is 70%. New rainfall amounts between 1 and 2 cm possible. Wednesday: A 50 percent chance of showers and thunderstorms, mainly before 4pm. Mostly cloudy, with a high near 25. Northeast wind around 10 km/h, with gusts as high as 20 km/h. Wednesday Night: A slight chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 20. East wind 5 to 10 km/h, with gusts as high as 20 km/h. Chance of precipitation is 70%. Thursday: Showers likely and possibly a thunderstorm before 1pm. Mostly cloudy, with a high near 28. Chance of precipitation is 60%. Thursday Night: A 40 percent chance of showers and thunderstorms after 1am. Mostly cloudy, with a low around 19. Friday: A chance of showers before 1pm. Partly sunny, with a high near 27. Friday Night: A chance of showers. Partly cloudy, with a low around 19. Saturday: A chance of showers, with thunderstorms also possible after 1pm. Partly sunny, with a high near 29. Saturday Night: Showers likely. Mostly cloudy, with a low around 18. Sunday: A chance of showers. Partly sunny, with a high near 24. Sunday Night: Mostly cloudy, with a low around 14. Monday: Mostly sunny, with a high near 23. | |
| Ottawa IL 41.35°N 88.85°W | |
Visit your local NWS office at: https://www.weather.gov/lot |
