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Saint John, MO Weather
Current conditions
Observed at St. Louis Lambert International Airport · 24 min ago
Forecast
10-day-
Tonight
Mostly clear, with a low around 50. Southeast wind 0 to 5 mph.
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Wednesday
Sunny, with a high near 73. East wind 0 to 3 mph.
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Wednesday Night
Mostly clear, with a low around 49. Northeast wind around 2 mph.
National Weather Service forecast updated 21 hrs ago.
Hourly
Hourly forecast- Now51°
- 5 AM51°
- 6 AM51°
- 7 AM50°
- 8 AM51°
- 9 AM54°
- 10 AM60°
- 11 AM64°
- 12 PM68°
- 1 PM71°
- 2 PM72°
- 3 PM72°
- 4 PM73°
- 5 PM72°
- 6 PM68°
- 7 PM65°
- 8 PM61°
- 9 PM60°
- 10 PM58°
- 11 PM57°
- Thu12 AM56°
- 1 AM54°
- 2 AM53°
- 3 AM51°
Daily forecast
Details- TueOct 20Sunny50°72°
- TodayOct 21Sunny49°73°
- ThuOct 22Sunny51°75°
- FriOct 23Sunny51°75°
- SatOct 24Mostly Sunny54°75°
- SunOct 25Partly Sunny54°77°
- MonOct 26Partly Sunny51°74°
- TueOct 27Mostly sunny0.03 in50°60°
- WedOct 28Sunny44°57°
Days after the National Weather Service's seven are MET Norway's outlook, a computer model with no forecaster's review.
Radar
Full mapWeather news near Saint John
More weather news- St. Louis Weather Forecast Friday Through Thursday
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Air quality
Air quality is satisfactory, and air pollution poses little or no risk.
Saint Louis, MO reporting area · 1 hr ago. Data from AirNow (EPA and its state, local and tribal partners); preliminary and subject to change.
Sun & moon
Almanac
MonthlySt Louis Area, records since 1874. Normals 1991–2020. Data from NOAA's Regional Climate Centers (ACIS).
Nearby
- St. Louis 16 km
- O'Fallon 32 km
- Saint Charles 14 km
- Saint Peters 26 km
- Florissant 9 km
- Chesterfield 21 km
- Belleville 38 km
- Oakville 27 km
- Wildwood 31 km
- Wentzville 45 km
- University City 7 km
- Ballwin 22 km
Forecasters' discussion
From the National Weather Service office in LSX, issued 1 hr ago
Key Messages
- Seasonably warm and dry weather will last through this weekend.
Short Term
Issued at 257 AM CDT Wed Oct 21 2026
No significant changes have been made to the forecast. The mid-level omega blocking pattern and surface high pressure influence will keep our sensible weather consistently dry, and insolation will act as the sole driver for our gradually warming temperatures. Expect highs generally in the mid-70s today and tomorrow with lows in the 40s to low-50s in between.
Long Term
Issued at 257 AM CDT Wed Oct 21 2026
The pattern begins to change late this week. A mid-level longwave trough circling over the Four Corners area is expected to split, with its poleward section phasing into another trough traversing western Canada. This shift will pull a cold front into the Upper Midwest Saturday and orient it zonally on Sunday as the shortwave zips into eastern Canada. The Mid-Mississippi Valley will remain well south of the cold front over the weekend, and our temperature trends will reflect that. LREF probabilities of 1pm temperatures >69 degrees Saturday and Sunday both range from 75-100%, and the NBM max temperature spread for each day is only 3 degrees. The cold front is expected to finally push into the region on Tuesday, but cooler weather is not guaranteed especially for locations south of I-70. Guidance suggests that the front may be weakening as it arrives, and that it may become stationary before it clears the area. This would mean that less cool air would filter into less of the CWA and that the warm streak may continue through Tuesday. Confidence in this, or for any solution, is still very low given the timeframe in question. Again, the NBM max temperature spread reflects this well as it climbs to 10+ degrees on Tuesday and nearly 20 degrees on Wednesday.
Aviation
Issued at 1000 PM CDT Tue Oct 20 2026
Mainly dry and VFR conditions are expected through the period with light winds.
Forecasts, observations and alerts in the United States come from the National Weather Service (NOAA); radar from NOAA's Multi-Radar Multi-Sensor system; satellite imagery from NASA's Global Imagery Browse Services (GIBS) and NOAA's GOES satellites; the map from the U.S. Geological Survey's National Map; air quality from AirNow (EPA and its partners); hurricane information from the National Hurricane Center; climate normals and records from NOAA's Regional Climate Centers (ACIS). Forecasts outside the United States and the UV index: MET Norway (CC BY 4.0); observations outside the U.S.: airport reports via NOAA's Aviation Weather Center. Place names: GeoNames (CC BY 4.0). Data are copied on a schedule and may lag the sources; for warnings that affect your safety, follow your local National Weather Service office and emergency officials. Weather news is drawn from the 4Search index and reflects what the press published. Terms of use.