Cortland, IL Weather Forecast & Current Conditions

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Cortland, IL Weather Maps

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Cortland Weather Map
UTC Time: 9/19/2026, 07:43
Your Time:
Aeronautical Observation: Automated synoptic observations via NWS Gateway.
Auto-refresh in: 5:02

Cortland, IL Regional Weather

Expires:202609190800;;698026
ASUS43 KLOT 190710
RWRIL 

ILLINOIS REGIONAL WEATHER ROUNDUP
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
200 AM CDT SAT SEP 19 2026

NOTE: "FAIR" INDICATES FEW OR NO CLOUDS BELOW 12,000 FEET WITH NO
SIGNIFICANT WEATHER AND/OR OBSTRUCTIONS TO VISIBILITY.

* THESE STATIONS ARE NOT UNDER NWS QUALITY CONTROL. THEY ALSO MAY NOT
  REPORT WEATHER SUCH AS PRECIPITATION OR FOG.


ILZ003-004-008-010-011-017-018-190800-
NORTH CENTRAL ILLINOIS
  
CITY           SKY/WX    TMP DP  RH WIND       PRES   REMARKS
ROCKFORD       CLOUDY    67  60  78 SE7       29.99F TC  19           
FREEPORT*      CLOUDY    66  64  91 N9        30.02R TC  19           
ROCHELLE*      CLOUDY    66  62  85 SE8       29.98F TC  19           
DE KALB*       CLOUDY    67  61  81 SE15      30.00F TC  20           
PERU*          CLOUDY   N/A N/A N/A SE6       29.98F                  
$$


SKY/WX - Weather  TMP - Temperature  DP - Dew Point  RH - Humidity
WIND - Wind Direction/Speed PRES - Barometric Pressure VSB - Visibility
WCI - Wind Chill Index E13G22 Wind - East Wind 13 mph/Gusts of 22 mph

Cortland, IL

Tonight
Thunderstorms
65°18°
100%
Saturday
Thunderstorms
78°/ 62° 26°/ 17°
100%
Sunday
Thunderstorms
68°/ 55° 20°/ 13°
70%
Monday
Rain Showers
65°/ 50° 18°/ 10°
50%
Tuesday
Rain Showers
62°/ 48° 17°/
20%
Wednesday
Cloudy
65°/ 52° 18°/ 11°
0%
Thursday
Mostly Cloudy
68°/ 52° 20°/ 11°
0%
Friday
Mostly Cloudy
72°22°
0%

Night: A chance of showers and thunderstorms after midnight, then showers with thunderstorms likely late. Some thunderstorms may produce heavy rainfall late. Locally heavy rainfall possible late. Near steady temperature in the mid 60s. Southeast winds around 10 mph. Chance of precipitation near 100 percent.

Aurora, IL

Tonight
Thunderstorms
65°18°
90%
Saturday
Thunderstorms
78°/ 62° 26°/ 17°
100%
Sunday
Thunderstorms
68°/ 55° 20°/ 13°
60%
Monday
Rain Showers
65°/ 52° 18°/ 11°
40%
Tuesday
Rain Showers
62°/ 50° 17°/ 10°
20%
Wednesday
Mostly Cloudy
65°/ 52° 18°/ 11°
0%
Thursday
Mostly Cloudy
68°/ 52° 20°/ 11°
0%
Friday
Mostly Cloudy
72°22°
0%

Night: A chance of showers and thunderstorms after midnight, then showers with thunderstorms likely late. Some thunderstorms may produce heavy rainfall late. Locally heavy rainfall possible late. Near steady temperature in the mid 60s. East winds around 10 mph. Chance of precipitation 90 percent.

Rochelle, IL

Tonight
Thunderstorms
65°18°
100%
Saturday
Thunderstorms
78°/ 62° 26°/ 17°
100%
Sunday
Thunderstorms
68°/ 55° 20°/ 13°
60%
Monday
Rain Showers
65°/ 48° 18°/
50%
Tuesday
Mostly Cloudy
62°/ 48° 17°/
0%
Wednesday
Cloudy
65°/ 48° 18°/
0%
Thursday
Mostly Cloudy
68°/ 50° 20°/ 10°
0%
Friday
Cloudy
72°22°
0%

Night: Showers likely after midnight. Thunderstorms likely. Showers late. Some thunderstorms may produce heavy rainfall. Locally heavy rainfall possible late. Near steady temperature in the mid 60s. Southeast winds 5 to 10 mph. Chance of precipitation near 100 percent.

Oswego, IL

Tonight
Thunderstorms
65°18°
90%
Saturday
Thunderstorms
80°/ 65° 27°/ 18°
100%
Sunday
Thunderstorms
72°/ 58° 22°/ 14°
70%
Monday
Rain Showers
65°/ 52° 18°/ 11°
50%
Tuesday
Rain Showers
65°/ 52° 18°/ 11°
20%
Wednesday
Mostly Cloudy
68°/ 52° 20°/ 11°
0%
Thursday
Mostly Cloudy
68°/ 52° 20°/ 11°
0%
Friday
Cloudy
72°22°
0%

Night: A slight chance of showers and thunderstorms after midnight, then showers with thunderstorms likely late. Some thunderstorms may produce heavy rainfall late. Near steady temperature in the mid 60s. Southeast winds around 10 mph. Chance of precipitation 90 percent.

Belvidere, IL

Tonight
Thunderstorms
65°18°
100%
Saturday
Thunderstorms
75°/ 62° 24°/ 17°
100%
Sunday
Thunderstorms
68°/ 55° 20°/ 13°
50%
Monday
Rain Showers
62°/ 48° 17°/
40%
Tuesday
Mostly Cloudy
62°/ 48° 17°/
0%
Wednesday
Mostly Cloudy
65°/ 48° 18°/
0%
Thursday
Mostly Cloudy
65°/ 50° 18°/ 10°
0%
Friday
Mostly Cloudy
70°21°
0%

Night: Thunderstorms likely after midnight. Showers. Thunderstorms likely late. Some thunderstorms may produce heavy rainfall after midnight. Locally heavy rainfall possible late. Near steady temperature in the mid 60s. East winds around 10 mph. Chance of precipitation near 100 percent.

Dixon, IL

Tonight
Thunderstorms
65°18°
90%
Saturday
Thunderstorms
80°/ 62° 27°/ 17°
100%
Sunday
Thunderstorms
70°/ 55° 21°/ 13°
70%
Monday
Rain Showers
65°/ 52° 18°/ 11°
50%
Tuesday
Rain Showers
62°/ 48° 17°/
20%
Wednesday
Cloudy
65°/ 52° 18°/ 11°
0%
Thursday
Mostly Cloudy
68°/ 52° 20°/ 11°
0%
Friday
Cloudy
72°22°
0%

Night: A chance of showers and thunderstorms after midnight, then showers with thunderstorms likely late. Some thunderstorms may produce heavy rainfall late. Near steady temperature in the mid 60s. Southeast winds 5 to 10 mph. Chance of precipitation 90 percent.

Crystal Lake, IL

Tonight
Thunderstorms
65°18°
100%
Saturday
Thunderstorms
75°/ 62° 24°/ 17°
100%
Sunday
Thunderstorms
68°/ 55° 20°/ 13°
50%
Monday
Rain Showers
62°/ 50° 17°/ 10°
30%
Tuesday
Mostly Cloudy
62°/ 48° 17°/
0%
Wednesday
Mostly Cloudy
65°/ 52° 18°/ 11°
0%
Thursday
Mostly Cloudy
65°/ 52° 18°/ 11°
0%
Friday
Mostly Cloudy
70°21°
0%

Night: Showers with thunderstorms likely. Some thunderstorms may produce heavy rainfall. Locally heavy rainfall possible late. Near steady temperature in the mid 60s. East winds around 10 mph. Chance of precipitation near 100 percent.

Ottawa, IL

Tonight
Thunderstorms
68°20°
70%
Saturday
Thunderstorms
82°/ 65° 28°/ 18°
100%
Sunday
Thunderstorms
72°/ 58° 22°/ 14°
70%
Monday
Rain Showers
65°/ 52° 18°/ 11°
60%
Tuesday
Rain Showers
65°/ 52° 18°/ 11°
20%
Wednesday
Cloudy
68°/ 52° 20°/ 11°
0%
Thursday
Mostly Cloudy
68°/ 55° 20°/ 13°
0%
Friday
Cloudy
72°22°
0%

Night: A slight chance of showers and thunderstorms after midnight, then thunderstorms likely and a chance of showers late. Near steady temperature in the upper 60s. Southeast winds 5 to 10 mph. Chance of precipitation 70 percent.

Naperville, IL

Tonight
Thunderstorms
62°17°
90%
Saturday
Thunderstorms
78°/ 65° 26°/ 18°
100%
Sunday
Thunderstorms
68°/ 58° 20°/ 14°
60%
Monday
Rain Showers
65°/ 52° 18°/ 11°
30%
Tuesday
Rain Showers
62°/ 52° 17°/ 11°
20%
Wednesday
Mostly Cloudy
65°/ 55° 18°/ 13°
0%
Thursday
Mostly Cloudy
65°/ 55° 18°/ 13°
0%
Friday
Mostly Cloudy
70°21°
0%

Night: A chance of showers and thunderstorms after midnight, then showers with thunderstorms likely late. Some thunderstorms may produce heavy rainfall late. Locally heavy rainfall possible late. Lows in the lower 60s. East winds around 10 mph. Chance of precipitation 90 percent.

Rockford, IL

Tonight
Thunderstorms
65°18°
100%
Saturday
Thunderstorms
75°/ 60° 24°/ 16°
100%
Sunday
Thunderstorms
68°/ 55° 20°/ 13°
50%
Monday
Rain Showers
62°/ 48° 17°/
40%
Tuesday
Mostly Cloudy
62°/ 48° 17°/
0%
Wednesday
Cloudy
65°/ 48° 18°/
0%
Thursday
Mostly Cloudy
65°/ 48° 18°/
0%
Friday
Mostly Cloudy
70°21°
0%

Night: Thunderstorms likely after midnight. Showers. Thunderstorms likely late. Some thunderstorms may produce heavy rainfall after midnight. Locally heavy rainfall possible late. Near steady temperature in the mid 60s. East winds around 10 mph. Chance of precipitation near 100 percent.

Evanston, IL

Tonight
Thunderstorms
62°17°
90%
Saturday
Thunderstorms
75°/ 62° 24°/ 17°
100%
Sunday
Thunderstorms
68°/ 55° 20°/ 13°
60%
Monday
Rain Showers
65°/ 52° 18°/ 11°
30%
Tuesday
Mostly Cloudy
62°/ 52° 17°/ 11°
0%
Wednesday
Mostly Cloudy
65°/ 52° 18°/ 11°
0%
Thursday
Mostly Cloudy
65°/ 55° 18°/ 13°
0%
Friday
Mostly Cloudy
70°21°
0%

Night: Thunderstorms likely after midnight. Showers. Thunderstorms likely late. Some thunderstorms may produce heavy rainfall late. Lows in the lower 60s. East winds around 10 mph. Chance of precipitation 90 percent.

Joliet, IL

Tonight
Thunderstorms
65°18°
70%
Saturday
Thunderstorms
78°/ 65° 26°/ 18°
100%
Sunday
Thunderstorms
72°/ 58° 22°/ 14°
70%
Monday
Rain Showers
65°/ 52° 18°/ 11°
50%
Tuesday
Rain Showers
62°/ 52° 17°/ 11°
20%
Wednesday
Mostly Cloudy
65°/ 52° 18°/ 11°
0%
Thursday
Mostly Cloudy
68°/ 55° 20°/ 13°
0%
Friday
Mostly Cloudy
72°22°
0%

Night: A slight chance of showers and thunderstorms after midnight, then showers and thunderstorms likely late. Some thunderstorms may produce heavy rainfall late. Near steady temperature in the mid 60s. Southeast winds around 10 mph. Chance of precipitation 70 percent.

Waukegan, IL

Tonight
Thunderstorms
62°17°
100%
Saturday
Thunderstorms
75°/ 62° 24°/ 17°
100%
Sunday
Thunderstorms
68°/ 55° 20°/ 13°
50%
Monday
Rain Showers
65°/ 52° 18°/ 11°
20%
Tuesday
Mostly Cloudy
62°/ 52° 17°/ 11°
0%
Wednesday
Mostly Cloudy
62°/ 52° 17°/ 11°
0%
Thursday
Mostly Cloudy
65°/ 52° 18°/ 11°
0%
Friday
Mostly Cloudy
68°20°
0%

Night: Showers and thunderstorms likely after midnight, then showers with thunderstorms likely late. Some thunderstorms may produce heavy rainfall late. Locally heavy rainfall possible late. Lows in the lower 60s. East winds 10 to 15 mph. Chance of precipitation near 100 percent.

Whitewater, WI

Tonight
Thunderstorms
62°17°
100%
Saturday
Thunderstorms
72°/ 60° 22°/ 16°
100%
Sunday
Rain Showers
65°/ 52° 18°/ 11°
40%
Monday
Rain Showers
62°/ 48° 17°/
20%
Tuesday
Partly Cloudy
60°/ 48° 16°/
0%
Wednesday
Partly Cloudy
62°/ 48° 17°/
0%
Thursday
Partly Cloudy
65°/ 50° 18°/ 10°
0%
Friday
Partly Cloudy
68°20°
0%

Night: Showers and scattered thunderstorms. Locally heavy rainfall possible. Near steady temperature in the lower 60s. East winds 5 to 15 mph. Chance of precipitation near 100 percent.

Morris, IL

Tonight
Thunderstorms
68°20°
70%
Saturday
Thunderstorms
82°/ 68° 28°/ 20°
90%
Sunday
Thunderstorms
72°/ 58° 22°/ 14°
70%
Monday
Rain Showers
68°/ 52° 20°/ 11°
60%
Tuesday
Rain Showers
65°/ 52° 18°/ 11°
20%
Wednesday
Mostly Cloudy
68°/ 55° 20°/ 13°
0%
Thursday
Mostly Cloudy
70°/ 55° 21°/ 13°
0%
Friday
Cloudy
75°24°
0%

Night: Thunderstorms likely and a chance of showers late. Near steady temperature in the upper 60s. Southeast winds 5 to 10 mph. Chance of precipitation 70 percent.

Chicago, IL

Tonight
Thunderstorms
65°18°
90%
Saturday
Thunderstorms
75°/ 65° 24°/ 18°
100%
Sunday
Thunderstorms
70°/ 58° 21°/ 14°
60%
Monday
Rain Showers
65°/ 55° 18°/ 13°
30%
Tuesday
Rain Showers
62°/ 55° 17°/ 13°
20%
Wednesday
Mostly Cloudy
65°/ 55° 18°/ 13°
0%
Thursday
Mostly Cloudy
65°/ 55° 18°/ 13°
0%
Friday
Mostly Cloudy
68°20°
0%

Night: A slight chance of showers and thunderstorms after midnight, then showers with thunderstorms likely late. Some thunderstorms may produce heavy rainfall late. Locally heavy rainfall possible late. Near steady temperature in the mid 60s. Southeast winds 10 to 15 mph. Chance of precipitation 90 percent.

Calumet City, IL

Tonight
Thunderstorms
65°18°
70%
Saturday
Thunderstorms
78°/ 65° 26°/ 18°
100%
Sunday
Thunderstorms
68°/ 55° 20°/ 13°
70%
Monday
Rain Showers
65°/ 52° 18°/ 11°
40%
Tuesday
Rain Showers
62°/ 52° 17°/ 11°
20%
Wednesday
Mostly Cloudy
65°/ 55° 18°/ 13°
0%
Thursday
Mostly Cloudy
68°/ 55° 20°/ 13°
0%
Friday
Mostly Cloudy
72°22°
0%

Night: A slight chance of showers and thunderstorms after midnight, then showers and thunderstorms likely late. Some thunderstorms may produce heavy rainfall late. Near steady temperature in the mid 60s. Southeast winds around 10 mph. Chance of precipitation 70 percent.

Princeton, IL

Tonight
Thunderstorms
68°20°
50%
Saturday
Thunderstorms
82°/ 65° 28°/ 18°
100%
Sunday
Rain Showers
72°/ 58° 22°/ 14°
90%
Monday
Rain Showers
65°/ 52° 18°/ 11°
70%
Tue Night
Cloudy
52°11°
0%
Wed Night
Cloudy
52°11°
0%
Thursday
Partly Cloudy
68°/ 52° 20°/ 11°
0%

Night: Mostly cloudy with a chance of showers and thunderstorms. Patchy fog. Near steady temperature in the upper 60s. Southeast winds 5 to 10 mph. Chance of rain 50 percent.

Channahon, IL

Tonight
Thunderstorms
65°18°
70%
Saturday
Thunderstorms
82°/ 65° 28°/ 18°
100%
Sunday
Thunderstorms
72°/ 58° 22°/ 14°
70%
Monday
Rain Showers
65°/ 52° 18°/ 11°
50%
Tuesday
Rain Showers
65°/ 52° 18°/ 11°
20%
Wednesday
Mostly Cloudy
68°/ 52° 20°/ 11°
0%
Thursday
Mostly Cloudy
68°/ 55° 20°/ 13°
0%
Friday
Cloudy
72°22°
0%

Night: Showers and thunderstorms likely late. Near steady temperature in the mid 60s. Southeast winds 5 to 10 mph. Chance of precipitation 70 percent.

Janesville, WI

Tonight
Thunderstorms
62°17°
100%
Saturday
Thunderstorms
72°/ 60° 22°/ 16°
100%
Sunday
Rain Showers
65°/ 52° 18°/ 11°
30%
Monday
Rain Showers
62°/ 48° 17°/
30%
Tuesday
Partly Cloudy
62°/ 48° 17°/
0%
Wednesday
Partly Cloudy
65°/ 48° 18°/
0%
Thursday
Partly Cloudy
65°/ 48° 18°/
0%
Friday
Partly Cloudy
68°20°
0%

Night: Showers and scattered thunderstorms. Locally heavy rainfall possible. Near steady temperature in the lower 60s. East winds 10 to 15 mph. Chance of precipitation near 100 percent.

Names listed above may include county names.

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