Mchenry, IL 60051 Weather

McHenry County4:01 PM CDT42.35°N, 88.23°W

Current conditions

Sunny
67°
Sunny
Feels like 67°
High 68°·Low 40°
WindE 5 mph
Humidity47%
Dew point46°
Cloud cover6%
UV index1 Low
Sunrise7:12 AM
Sunset6:05 PM

Forecast for this hour (no station report in the last two hours)

Forecast

10-day

  • Today

    Sunny. High near 68, with temperatures falling to around 64 in the afternoon. East southeast wind 0 to 10 mph.

  • Tonight

    Patchy fog after 4am. Partly cloudy. Low around 40, with temperatures rising to around 42 overnight. East wind 0 to 5 mph.

  • Wednesday

    Patchy fog before 8am. Mostly sunny. High near 71, with temperatures falling to around 67 in the afternoon. West wind 0 to 5 mph.

National Weather Service forecast updated 6 hrs ago.

Hourly

Hourly forecast
  1. Now Sunny 67°
  2. 5 PM Sunny 64°
  3. 6 PM Clear 59°
  4. 7 PM Mostly Clear 54°
  5. 8 PM Mostly Clear 51°
  6. 9 PM Partly Cloudy 49°
  7. 10 PM Partly Cloudy 48°
  8. 11 PM Partly Cloudy 47°
  9. Wed12 AM Partly Cloudy 46°
  10. 1 AM Partly Cloudy 45°
  11. 2 AM Partly Cloudy 44°
  12. 3 AM Partly Cloudy 43°
  13. 4 AM Patchy Fog 42°
  14. 5 AM Patchy Fog 42°
  15. 6 AM Patchy Fog 41°
  16. 7 AM Patchy Fog 40°
  17. 8 AM Mostly Sunny 43°
  18. 9 AM Mostly Sunny 50°
  19. 10 AM Mostly Sunny 57°
  20. 11 AM Sunny 62°
  21. 12 PM Sunny 66°
  22. 1 PM Sunny 68°
  23. 2 PM Sunny 69°
  24. 3 PM Sunny 70°

10-day forecast

Details
  1. TodayOct 20 Sunny Sunny40°68°
  2. WedOct 21 Patchy Fog then Mostly Sunny Patchy Fog then Mostly Sunny45°71°
  3. ThuOct 22 Sunny Sunny46°70°
  4. FriOct 23 Sunny Sunny46°67°
  5. SatOct 24 Mostly Sunny Mostly Sunny50°67°
  6. SunOct 25 Partly Sunny Partly Sunny47°69°
  7. MonOct 26 Partly Sunny then Slight Chance Rain Showers Partly Sunny then Slight Chance Rain Showers15%43°65°
  8. TueOct 27 Cloudy Cloudy44°55°
  9. WedOct 28 Cloudy Cloudy43°54°
  10. ThuOct 29 Sunny Sunny40°53°

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

Radar

Full map
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Weather news near McHenry

More weather news

Air quality

77
Moderate
Fine particles (PM2.5)

Acceptable. Unusually sensitive people should consider limiting prolonged outdoor exertion.

Forecast

  • TueModerate
  • WedModerate
  • ThuModerate

North and West Suburbs (Chicago), IL reporting area · 1 hr ago. Data from AirNow (EPA and its state, local and tribal partners); preliminary and subject to change.

Sun & moon

Sunrise 7:12 AM
Sunset 6:05 PM
Daylight 10 h 52 min (−2 min 43 s tomorrow)
Waxing Gibbous · 71% lit
Moonrise 3:26 PM Moonset 1:04 AM
Full moon Oct 26 New moon Nov 9

Almanac

Monthly
Normal high / low61° / 41°
Record high83° (1953)
Record low22° (1952)
Wettest1.51 in (1982)
Yesterday64° / 38°
Month to date3.11 in (normal 1.98 in)

Lake Geneva Wwtp, records since 1945. Normals 1991–2020. Data from NOAA's Regional Climate Centers (ACIS).

Nearby

Forecasters' discussion

From the National Weather Service office in LOT, issued 1 hr ago

Key Messages

- Areas of fog, including potentially dense fog, may develop again late tonight into early Wednesday morning in and near the Chicago metro.

- An extended period of dry and above to much above average temperatures is expected through the upcoming weekend.

Discussion

Issued at 226 PM CDT Tue Oct 20 2026

An Omega block that is in place over the CONUS is expected to persist through the end of the week. The associated ridge axis will only ever so slowly crawl eastward over the coming days, which will maintain broad surface high pressure across the region. As a result, dry conditions with an abundance of sunshine will continue through the remainder of the week with high temperatures remaining above to well above normal for this time of year. Daily lake breezes will cause the coolest (low- mid 60s) high temperatures to be observed near Lake Michigan each day.

Much like last night/early this morning, optimal radiational cooling conditions will likely allow for fog to develop late tonight into tomorrow morning and possibly again in the coming nights/mornings. This will particularly be the case in and near the Chicago metro within the footprint of the marine-influenced air brought inland during the daytime, where the fog could become dense once again.

There is pretty good ensemble agreement at this point in time that the blocking pattern will break down by early next week. This will allow for a cold front to drop through the region sometime on Monday or Tuesday, resulting in a return to cooler and more seasonable temperatures for the middle of next week. The frontal passage may bring a chance for precipitation to the area early-mid next week, but support for this across the latest suite of ensemble guidance is not ubiquitous, and there are considerable temporal differences with when this next potential opportunity for precipitation may arrive as well.

Ogorek

Aviation

Issued at 1255 PM CDT Tue Oct 20 2026

Key aviation forecast messages:

- IFR or lower VSBYs in BR/FG may develop again early WED AM.

The primary concern through the period is the potential for fog near Lake Michigan early Wednesday morning, some of which may become locally dense. Model guidance that performed well with this morning's dense fog depicts another round of fog development over a similar area and extends slightly farther southeast. Have accordingly included MDW with the reduced VSBYs as low as 1 SM with this update to hint at increasing confidence in fog development. If this signal persists and additional guidance begins to pick up on the potential for dense fog, LIFR (or lower) conditions may need to be introduced with later updates.

Otherwise winds will remain light (under 10 kt) initially out of the SE, turning E to ENE behind a weak lake breeze this afternoon. Winds then ease and become light and variable again overnight eventually settling into a SSW direction after daybreak Wednesday.

Petr

Lot Watches

IL...None. IN...None. LM...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.