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St. Augustine Weather Forecast
| TONIGHT | LABOR DAY | MONDAY NIGHT | TUESDAY | TUESDAY NIGHT | WEDNESDAY | WEDNESDAY NIGHT | THURSDAY | THURSDAY NIGHT | FRIDAY | FRIDAY NIGHT | SATURDAY |
 |  | | |  |  | |  |  | |  | |
| Partly Cloudy | Mostly Sunny | Partly Cloudy | Mostly Sunny | Chance of Showers | Chance of Showers | Partly Cloudy | Partly Cloudy | Mostly Clear | Mostly Clear | Chance of Showers | Mostly Sunny |
| Lo: 60°FLo: 16°C | Hi: 81°FHi: 27°C | Lo: 61°FLo: 16°C | Hi: 89°FHi: 32°C | Lo: 71°FLo: 22°C | Hi: 89°FHi: 32°C | Hi: 81°FHi: 27°C Lo: 61°FLo: 16°C | Hi: 81°FHi: 27°C Lo: 61°FLo: 16°C | Hi: 85°FHi: 29°C Lo: 59°FLo: 15°C | Hi: 85°FHi: 29°C Lo: 59°FLo: 15°C | Lo: 61°FLo: 16°C | Hi: 85°FHi: 29°C |
| POP: 50% | POP: 70% | POP: 40% |
POP = Probability of Precipitation.
Weather Outlook Updated: 337 PM CDT Sun Sep 06 2026 
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Issued: 131 PM CDT Sun Sep 6 2026
Key Messages
- Heat Returns Midweek: Hot and muggy conditions return Tuesday and Wednesday. Temperatures will top out in the 90s both days, with an influx of moisture pushing heat indices to around 100 degrees south of I-72 Wednesday afternoon.
- Midweek Storm Potential: A passing front brings a 40-60% chance for scattered showers and thunderstorms on Wednesday, primarily across the Illinois River Valley.
- Higher Storm Chances Late Week: Confidence is higher (60% to 80% chance) for widespread thunders...