Boulder, IL Weather Forecast
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Boulder Weather Forecast
| THIS AFTERNOON | TONIGHT | SATURDAY | SATURDAY NIGHT | SUNDAY | SUNDAY NIGHT | MONDAY | TUESDAY | WEDNESDAY | WEDNESDAY NIGHT | THURSDAY |
| Sunny | Mostly Clear | Thunderstorms | Mostly Clear | Sunny | Mostly Clear | Mostly Clear | Mostly Clear | Mostly Clear | Chance of Showers | Chance of Showers |
| Hi: 99°FHi: 37°C | Lo: 75°FLo: 24°C | Hi: 100°FHi: 38°C | Lo: 71°FLo: 22°C | Hi: 91°FHi: 33°C | Hi: 91°FHi: 33°C Lo: 65°FLo: 18°C | Hi: 91°FHi: 33°C Lo: 65°FLo: 18°C | Hi: 99°FHi: 37°C Lo: 71°FLo: 22°C | Hi: 99°FHi: 37°C Lo: 71°FLo: 22°C | Lo: 75°FLo: 24°C | Hi: 91°FHi: 33°C |
| POP: 20% | POP: 20% | POP: 20% |
POP = Probability of Precipitation.
Weather Outlook Updated: 142 PM CDT Fri Sep 04 2026 

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Issued: 1221 PM CDT Fri Sep 4 2026
Key Messages
- A late summer heatwave will continue through Saturday before temperatures cool slightly Sunday into Labor Day.
- Another period of heat and near-record breaking temperatures is forecast Tuesday into Wednesday, but it is uncertain how long the heat persists thereafter.
Aviation
/18Z TAFS THROUGH 00Z SUNDAY/... Issued at 1219 PM CDT Fri Sep 4 2026
Dry/VFR conditions with diurnal cumulus dissipating this evening along with winds becoming light/variable are expected.
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