Sycamore, IL Weather

DeKalb County11:39 PM CDT41.99°N, 88.69°WElevation 873 ft

Current conditions

Clear
48°
Clear
Feels like 48°
High 73° Thursday·Low 42° tonight
WindCalm
Humidity93%
Dew point46°
Pressure30.23 inHg
Visibility8.0 mi
Cloud cover5%
UV index0 Low
Sunrise7:15 AM
Sunset6:05 PM

Observed at Aurora Municipal Airport · 1 hr ago

Forecast

10-day

  • Tonight

    Patchy fog after 3am. Mostly clear, with a low around 42. Wind around 0 mph.

  • Thursday

    Patchy fog before 9am. Sunny. High near 73, with temperatures falling to around 71 in the afternoon. North northeast wind around 0 mph.

  • Thursday Night

    Mostly clear, with a low around 47. East wind 0 to 5 mph.

National Weather Service forecast updated 7 hrs ago.

Hourly

Hourly forecast
  1. Now Clear 50°
  2. Thu12 AM Clear 47°
  3. 1 AM Clear 47°
  4. 2 AM Clear 46°
  5. 3 AM Patchy Fog 46°
  6. 4 AM Patchy Fog 45°
  7. 5 AM Patchy Fog 43°
  8. 6 AM Patchy Fog 42°
  9. 7 AM Patchy Fog 43°
  10. 8 AM Patchy Fog 44°
  11. 9 AM Sunny 51°
  12. 10 AM Sunny 60°
  13. 11 AM Sunny 65°
  14. 12 PM Sunny 69°
  15. 1 PM Sunny 71°
  16. 2 PM Sunny 72°
  17. 3 PM Sunny 73°
  18. 4 PM Sunny 73°
  19. 5 PM Sunny 71°
  20. 6 PM Clear 68°
  21. 7 PM Mostly Clear 62°
  22. 8 PM Mostly Clear 58°
  23. 9 PM Mostly Clear 55°
  24. 10 PM Mostly Clear 53°

10-day forecast

Details
  1. TonightOct 21 Mostly Clear then Patchy Fog Mostly Clear then Patchy Fog42°
  2. ThuOct 22 Patchy Fog then Sunny Patchy Fog then Sunny47°73°
  3. FriOct 23 Mostly Sunny Mostly Sunny48°72°
  4. SatOct 24 Partly Sunny Partly Sunny50°71°
  5. SunOct 25 Partly Sunny Partly Sunny50°73°
  6. MonOct 26 Partly Sunny Partly Sunny12%47°68°
  7. TueOct 27 Slight Chance Rain Showers Slight Chance Rain Showers19%44°62°
  8. WedOct 28 Slight Chance Rain Showers then Partly Sunny Slight Chance Rain Showers then Partly Sunny15%64°
  9. ThuOct 29 Cloudy Cloudy38°56°
  10. FriOct 30 Sunny Sunny40°56°

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 Sycamore

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Air quality

63
Moderate
Fine particles (PM2.5)

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

Forecast

  • WedModerate
  • ThuModerate
  • FriModerate

Aurora and Elgin, 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 7:15 AM
Sunset 6:05 PM
Daylight 10 h 50 min (−2 min 41 s tomorrow)
Waxing Gibbous · 82% lit
Moonrise 3:49 PM Moonset 2:12 AM
Full moon Oct 26 New moon Nov 9

Almanac

Monthly
Normal high / low60° / 39°
Record high83° (2003)
Record low24° (2018)
Wettest0.76 in (1972)
Month to date3.20 in (normal 1.96 in)

De Kalb, records since 1966. Normals 1991–2020. Data from NOAA's Regional Climate Centers (ACIS).

Nearby

Forecasters' discussion

From the National Weather Service office in LOT, issued 4 hrs ago

Key Messages

- The dry and unseasonably mild weather will continue through the upcoming weekend.

Discussion

Issued at 136 PM CDT Wed Oct 21 2026

An anomalously strong mid-level ridge over the central CONUS will anchor omega blocking across much of North America over the next several days. Meanwhile, an elongated surface ridge extending from the Lower Mississippi River Valley to the Canadian Maritimes is in the processes of congealing with another expansive high pressure shifting toward the Upper Great Lakes. As a result, quiet weather with unseasonably warm conditions will continue through the upcoming weekend. As was observed the past few mornings, generally clear skies and light/calm winds should promote shallow fog across primarily interior northern Illinois late tonight through sunrise Thursday.

The blocking pattern will slowly break down early next week as the ridge flattens and a southwestern upper-level low begins to meander toward the central CONUS. A series of smaller troughs on the periphery of a developing longwave trough across the north Pacific and western Canada will eventually pick up the southwestern low. Consensus guidance suggests that the influence of the low on our area could occur as early as Monday night, but more likely Tuesday and Wednesday. Cooler and more seasonable conditions would accompany this system.

Kluber

Aviation

Issued at 641 PM CDT Wed Oct 21 2026

Main aviation forecast concern is the potential for patchy IFR/LIFR fog to develop mainly northwest of Chicago early Thursday morning.

Surface high pressure ridge has shifted east of the area across lower MI/IN early this evening. Light south-southwest surface winds at the terminals are expected to quickly become light/variable or just calm early this evening, though there may be a brief (1-hour)period of light east winds at ORD/MDW/GYY as a weak lake breeze decays. The pressure gradient will remain weak into Thursday, keeping winds light/variable through the morning before becoming light (5-6 kts) northeast and eventually east in the afternoon/evening.

Clear skies and light/calm winds tonight will allow for ideal radiative cooling conditions, allowing shallow fog to develop in spots once again. This appears most likely across southern WI/northeast IA and far northern/northwest IL KRFD) where surface dew points remained in the mid-upper 40s during peak mixing Wednesday afternoon. While guidance is not too aggressive with lower visibilities, have maintained a 2SM IFR tempo and MIFG in the KRFD TAF, and will monitor overnight for tactical lower vsbys. The drier low-level airmass to the southeast looks to be less conducive to fog development with southeastward extent. Have maintained a 3SM MIFG tempo at DPA, with VFR conditions for the other Chicago area terminals.

Ratzer

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.