Weather for St Charles, Missouri
Current Weather
Five Day Weather Forecast
Sat
H: 95°F
L: 76°F
Sun
H: 93°F
L: 76°F
Mon
H: 99°F
L: 76°F
Tue
H: 91°F
L: 71°F
Wed
H: 80°F
L: 65°F
Air Quality
Nitrogen Dioxide: 6.9 μg/m3
Sulphur Dioxide: 1.4 μg/m3
Ozone: 47 μg/m3
Astronomical
Sun Transit: 1:08 PM
Sunset: 8:25 PM
Daylight: 14 hrs 33 mins
Moon Transit: 4:57 PM
Moonset: 11:00 PM
Moon Phase: Waxing Crescent
Moon Illumination: 13.9%
Best Times for Fishing or Hunting
Major Periods
4:00 AM - 6:30 AM4:27 PM - 6:57 PM
Minor Periods
12:00 AM - 12:00 AM10:13 AM - 11:43 AM
Action Rating: 2 out of 5
Heat Advisory issued July 18 at 3:04AM CDT until July 21 at 7:00PM CDT by NWS St Louis MO
Effective: Sat July 18, 2026, 3:04 AM
Expires: Sat July 18, 2026, 6:15 PM
* WHAT...Heat index values up to 105 expected. * WHERE...Portions of south central and southwest Illinois and central, east central, and southeast Missouri. * WHEN...From noon today to 7 PM CDT Tuesday. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses.
Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Young children and pets should never be left unattended in vehicles under any circumstances. Take extra precautions if you work or spend time outside. When possible reschedule strenuous activities to early morning or evening. Know the signs and symptoms of heat exhaustion and heat stroke. Wear lightweight and loose fitting clothing when possible. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency! Call 9 1 1.
Weather Forecast
Air Quality
Nitrogen Dioxide: 4.7 μg/m3
Sulphur Dioxide: 1.38 μg/m3
Ozone: 71.88 μg/m3
Astronomical
Sun Transit: 1:08 PM
Sunset: 8:25 PM
Daylight: 14 hrs 33 mins
Moon Transit: 4:57 PM
Moonset: 11:00 PM
Moon Phase: Waxing Crescent
Moon Illumination: 13.9%
Best Times for Fishing or Hunting
Major Periods
4:00 AM - 6:30 AM4:27 PM - 6:57 PM
Minor Periods
12:00 AM - 12:00 AM10:13 AM - 11:43 AM
Action Rating: 2 out of 5
Weather Forecast
Air Quality
Nitrogen Dioxide: 7.08 μg/m3
Sulphur Dioxide: 1.94 μg/m3
Ozone: 88.38 μg/m3
Astronomical
Sun Transit: 1:08 PM
Sunset: 8:24 PM
Daylight: 14 hrs 32 mins
Moon Transit: 5:40 PM
Moonset: 12:00 AM
Moon Phase: Waxing Crescent
Moon Illumination: 22.6%
Best Times for Fishing or Hunting
Major Periods
4:45 AM - 7:15 AM5:10 PM - 7:40 PM
Minor Periods
11:19 AM - 12:49 AM12:00 AM - 12:00 AM
Action Rating: 2 out of 5
Weather Forecast
Air Quality
Nitrogen Dioxide: 11.88 μg/m3
Sulphur Dioxide: 4.41 μg/m3
Ozone: 111.33 μg/m3
Astronomical
Sun Transit: 1:08 PM
Sunset: 8:23 PM
Daylight: 14 hrs 30 mins
Moon Transit: 6:24 PM
Moonset: 12:23 AM
Moon Phase: Waxing Crescent
Moon Illumination: 32.7%
Best Times for Fishing or Hunting
Major Periods
5:28 AM - 7:58 AM5:54 PM - 8:24 PM
Minor Periods
12:23 AM - 1:53 PM12:00 AM - 12:00 AM
Action Rating: 4 out of 5
Weather Forecast
Air Quality
Nitrogen Dioxide: 8.16 μg/m3
Sulphur Dioxide: 2.04 μg/m3
Ozone: 81.83 μg/m3
Astronomical
Sun Transit: 1:08 PM
Sunset: 8:23 PM
Daylight: 14 hrs 29 mins
Moon Transit: 7:08 PM
Moonset: 12:47 AM
Moon Phase: First Quarter
Moon Illumination: 43.7%
Best Times for Fishing or Hunting
Major Periods
6:12 AM - 8:42 AM6:38 PM - 9:08 PM
Minor Periods
1:26 PM - 2:56 PM12:00 AM - 12:00 AM
Action Rating: 3 out of 5
Weather Forecast
Air Quality
Nitrogen Dioxide: 7.63 μg/m3
Sulphur Dioxide: 1 μg/m3
Ozone: 67.25 μg/m3
Astronomical
Sun Transit: 1:08 PM
Sunset: 8:22 PM
Daylight: 14 hrs 27 mins
Moon Transit: 7:54 PM
Moonset: 12:14 AM
Moon Phase: First Quarter
Moon Illumination: 55.0%
Best Times for Fishing or Hunting
Major Periods
6:57 AM - 9:27 AM7:24 PM - 9:54 PM
Minor Periods
2:29 PM - 3:59 PM12:00 AM - 12:00 AM
Action Rating: 2 out of 5