Mount Vernon, IL 62864 Weather

Jefferson County6:14 PM CDT38.32°N, 88.91°W

Current conditions

Clear
74°
Clear
Feels like 72°
High 74° Wednesday·Low 43° tonight
WindCalm
Humidity31%
Dew point41°
Pressure30.29 inHg
Visibility10.0 mi
Cloud cover2%
UV index0 Low
Sunrise7:10 AM
Sunset6:12 PM

Observed at Centralia Municipal Airport · 1 hr ago

Forecast

10-day

  • Tonight

    Mostly clear, with a low around 43. North northeast wind around 1 mph.

  • Wednesday

    Sunny. High near 74, with temperatures falling to around 72 in the afternoon. North northeast wind around 1 mph.

  • Wednesday Night

    Clear, with a low around 45. Wind around 0 mph.

National Weather Service forecast updated 7 hrs ago.

Hourly

Hourly forecast
  1. Now Clear 67°
  2. 7 PM Clear 62°
  3. 8 PM Clear 55°
  4. 9 PM Clear 52°
  5. 10 PM Clear 50°
  6. 11 PM Clear 49°
  7. Wed12 AM Mostly Clear 48°
  8. 1 AM Mostly Clear 47°
  9. 2 AM Clear 46°
  10. 3 AM Clear 45°
  11. 4 AM Mostly Clear 44°
  12. 5 AM Mostly Clear 44°
  13. 6 AM Sunny 43°
  14. 7 AM Sunny 43°
  15. 8 AM Sunny 45°
  16. 9 AM Sunny 51°
  17. 10 AM Sunny 60°
  18. 11 AM Sunny 64°
  19. 12 PM Sunny 68°
  20. 1 PM Sunny 71°
  21. 2 PM Sunny 72°
  22. 3 PM Sunny 73°
  23. 4 PM Sunny 74°
  24. 5 PM Sunny 72°

10-day forecast

Details
  1. TodayOct 20 Sunny Sunny43°72°
  2. WedOct 21 Sunny Sunny45°74°
  3. ThuOct 22 Sunny Sunny45°76°
  4. FriOct 23 Sunny Sunny45°74°
  5. SatOct 24 Mostly Sunny Mostly Sunny47°76°
  6. SunOct 25 Mostly Sunny Mostly Sunny50°77°
  7. MonOct 26 Mostly Sunny Mostly Sunny48°75°
  8. TueOct 27 Mostly sunny Mostly sunny54°71°
  9. WedOct 28 Cloudy Cloudy0.02 in52°67°
  10. ThuOct 29 Cloudy Cloudy49°64°

Days after the National Weather Service's seven are MET Norway's outlook, a computer model with no forecaster's review.

Radar

Full map
Open the National Weather Service radar (the map here needs JavaScript).

Weather news near Mount Vernon

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Sun & moon

Sunrise 7:10 AM
Sunset 6:12 PM
Daylight 11 h 2 min (−2 min 21 s tomorrow)
Waxing Gibbous · 72% lit
Moonrise 3:21 PM Moonset 1:15 AM
Full moon Oct 26 New moon Nov 9

Almanac

Monthly
Normal high / low66° / 43°
Record high92° (1963)
Record low22° (2022)
Wettest2.41 in (2016)
Month to date0.51 in (normal 2.01 in)

Mt Vernon 3 Ne, records since 1895. Normals 1991–2020. Data from NOAA's Regional Climate Centers (ACIS).

Nearby

Forecasters' discussion

From the National Weather Service office in PAH, issued 6 hrs ago

Key Messages

- Areas of fog, some possibly dense, will develop near bodies of water early Wednesday morning.

- Near to slightly above normal temperatures are forecast for the next seven days.

- No rainfall is forecast for the next seven days.

Discussion

Issued at 1119 AM CDT Tue Oct 20 2026

Sprawling high pressure centered over the eastern and northeast CONUS combined with stable H5 ridging over the southern and central CONUS will bring quiet and stable weather to the region for the next week. Temperatures will be nearly the same each day, with highs in the lower to middle 70s and lows in the middle to upper 40s. The only mentionable weather concern will be for shallow (and possibly briefly dense) fog development early Wednesday morning near bodies of water (lakes, rivers, ponds, etc.). Have added fog to the forecast for these areas.

Aviation

Issued at 1119 AM CDT Tue Oct 20 2026

Shallow ground fog will develop early Wednesday morning along larger bodies of water. Have added fog to CGI between the 11-13z period to account for this. Otherwise, VFR conditions are expected with calm or very light NE winds and clear to mostly clear skies.

Pah Watches

IL...None. MO...None. IN...None. KY...None.

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.