Monthly outlook for DeKalb, IL: average high 59.3°, average low 46°. That is 2.1° above the climate normal for October. Precipitation is expected on 5 days (about 1.7 inches), against a normal of 5 days and 1.6 inches. The warmest day looks like 22 October (73.2°), the coolest 30 October (33.8°).
59.3°/46°
Average high / low
+2.1°
Above normal
5 / 5
Wet days / normal
1.7 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
21 October – 30 October
62.6°
57°
+3.1°
31 October – 9 November
53.8°
52.3°
+0.9°
10 November – 19 November
at normal
46.8°
—
October records over 66 years
87.1°3 October 2025All-time high
22.1°24 October 1981All-time low
Climate normals and records are computed from the nearest reference point — Sycamore (6 mi).
Thu, 2273° / 45°0
73 °
DeKalb, Thursday, 22 October
Clear. High 73°, low 45°.
Pressure30.27 inHg
Wind1.3 mph E
Humidity61%
Visibility6.2 mi
Dew point55°
Fri, 2370° / 47°0
70 °
DeKalb, Friday, 23 October
Overcast. High 70°, low 47°.
Pressure30.33 inHg
Wind5.7 mph S
Humidity59%
Visibility6.2 mi
Dew point53°
Sat, 2468° / 49°0
68 °
DeKalb, Saturday, 24 October
Overcast. High 68°, low 49°.
Pressure30.39 inHg
Wind8.5 mph S
Humidity56%
Visibility6.2 mi
Dew point48°
Sun, 2569° / 53°0
69 °
DeKalb, Sunday, 25 October
Overcast. High 69°, low 53°.
Pressure30.36 inHg
Wind6 mph S
Humidity54%
Visibility6.2 mi
Dew point49°
Mon, 2668° / 51°0
68 °
DeKalb, Monday, 26 October
Overcast. High 68°, low 51°.
Pressure30.24 inHg
Wind8 mph S
Humidity54%
Visibility—
Dew point49°
Tue, 2758° / 50°0.12
58 °
DeKalb, Tuesday, 27 October
Light rain. High 58°, low 50°.
Pressure30.21 inHg
Wind10.7 mph SE
Humidity71%
Visibility—
Dew point47°
Wed, 2855° / 43°0.52
55 °
DeKalb, Wednesday, 28 October
Rain. High 55°, low 43°.
Pressure29.97 inHg
Wind20.2 mph W
Humidity87%
Visibility—
Dew point51°
Thu, 2947° / 37°0
47 °
DeKalb, Thursday, 29 October
Clear. High 47°, low 37°.
Pressure30.30 inHg
Wind15.2 mph NW
Humidity49%
Visibility—
Dew point26°
Fri, 3049° / 34°0.04
49 °
DeKalb, Friday, 30 October
Light rain. High 49°, low 34°.
Pressure30.21 inHg
Wind9.5 mph SW
Humidity53%
Visibility—
Dew point29°
Sat, 3163° / 46°0
63 °
DeKalb, Saturday, 31 October
Overcast. High 63°, low 46°.
Pressure30.00 inHg
Wind14.9 mph SW
Humidity64%
Visibility—
Dew point45°
Sun, 0159° / 51°0
59 °
DeKalb, Sunday, 1 November
Light rain. High 59°, low 51°.
Pressure30.21 inHg
Wind7.8 mph SW
Humidity59%
Visibility—
Dew point44°
Mon, 0255° / 53°0.58
55 °
DeKalb, Monday, 2 November
Rain. High 55°, low 53°.
Pressure29.88 inHg
Wind13.2 mph E
Humidity98%
Visibility—
Dew point54°
Tue, 0354° / 48°0.42
54 °
DeKalb, Tuesday, 3 November
Light rain. High 54°, low 48°.
Pressure29.88 inHg
Wind23.4 mph NE
Humidity92%
Visibility—
Dew point51°
Wed, 0446° / 44°0.06
46 °
DeKalb, Wednesday, 4 November
Light rain. High 46°, low 44°.
Pressure30.30 inHg
Wind19.9 mph NE
Humidity66%
Visibility—
Dew point34°
Thu, 0546° / 42°0
46 °
DeKalb, Thursday, 5 November
Overcast. High 46°, low 42°.
Pressure30.09 inHg
Wind6.7 mph NE
Humidity82%
Visibility—
Dew point40°
From day 17 onward the outlook is built from 60-year climate statistics
Fri, 0651° / 37°0.09
51 °
DeKalb, Friday, 6 November
Climate normal for this date — 60-year average.
Average high51°
Average low37°
Average precipitation0.09 in
Chance of precipitation27%
Record high71° (1975)
Record low22° (1991)
Sat, 0751° / 37°0.03
51 °
DeKalb, Saturday, 7 November
Climate normal for this date — 60-year average.
Average high51°
Average low37°
Average precipitation0.03 in
Chance of precipitation20%
Record high67° (2009)
Record low13° (1991)
Sun, 0851° / 37°0.05
51 °
DeKalb, Sunday, 8 November
Climate normal for this date — 60-year average.
Average high51°
Average low37°
Average precipitation0.05 in
Chance of precipitation13%
Record high72° (2020)
Record low12° (1991)
Mon, 0951° / 37°0.12
51 °
DeKalb, Monday, 9 November
Climate normal for this date — 60-year average.
Average high51°
Average low37°
Average precipitation0.12 in
Chance of precipitation33%
Record high73° (1999)
Record low17° (1991)
Tue, 1049° / 35°0.1
49 °
DeKalb, Tuesday, 10 November
Climate normal for this date — 60-year average.
Average high49°
Average low35°
Average precipitation0.1 in
Chance of precipitation33%
Record high72° (2022)
Record low15° (2017)
Wed, 1147° / 33°0.07
47 °
DeKalb, Wednesday, 11 November
Climate normal for this date — 60-year average.
Average high47°
Average low33°
Average precipitation0.07 in
Chance of precipitation25%
Record high70° (1964)
Record low13° (2019)
Thu, 1246° / 32°0.06
46 °
DeKalb, Thursday, 12 November
Climate normal for this date — 60-year average.
Average high46°
Average low32°
Average precipitation0.06 in
Chance of precipitation23%
Record high65° (1964)
Record low1° (2019)
Fri, 1346° / 32°0.04
46 °
DeKalb, Friday, 13 November
Climate normal for this date — 60-year average.
Average high46°
Average low32°
Average precipitation0.04 in
Chance of precipitation20%
Record high70° (1999)
Record low1° (2019)
Sat, 1447° / 32°0.07
47 °
DeKalb, Saturday, 14 November
Climate normal for this date — 60-year average.
Average high47°
Average low32°
Average precipitation0.07 in
Chance of precipitation30%
Record high69° (1971)
Record low13° (1986)
Sun, 1546° / 33°0.08
46 °
DeKalb, Sunday, 15 November
Climate normal for this date — 60-year average.
Average high46°
Average low33°
Average precipitation0.08 in
Chance of precipitation23%
Record high69° (2025)
Record low14° (2019)
Mon, 1647° / 33°0.05
47 °
DeKalb, Monday, 16 November
Climate normal for this date — 60-year average.
Average high47°
Average low33°
Average precipitation0.05 in
Chance of precipitation15%
Record high63° (1988)
Record low18° (1997)
Tue, 1747° / 33°0.1
47 °
DeKalb, Tuesday, 17 November
Climate normal for this date — 60-year average.
Average high47°
Average low33°
Average precipitation0.1 in
Chance of precipitation28%
Record high71° (2016)
Record low14° (2014)
Wed, 1847° / 34°0.1
47 °
DeKalb, Wednesday, 18 November
Climate normal for this date — 60-year average.
Average high47°
Average low34°
Average precipitation0.1 in
Chance of precipitation25%
Record high68° (1999)
Record low11° (2014)
Thu, 1946° / 33°0.07
46 °
DeKalb, Thursday, 19 November
Climate normal for this date — 60-year average.
Average high46°
Average low33°
Average precipitation0.07 in
Chance of precipitation28%
Record high64° (1983)
Record low11° (2018)
About the monthly outlook
How accurate is a 30-day forecast?
The first 16 days come from weather models — reliable for the first 3–5 days and progressively less so after that. Days 17 through 30 for DeKalb, IL are built from the climate normal, the 60-year average, so they show typical weather for those dates rather than a specific forecast.
What does "above normal" mean?
We compare the forecast against the climate normal for those exact calendar days, computed from 60 years of observations. The deviation shows how much the coming month differs from a typical one.
Where do the 66-year records come from?
They are real temperature extremes recorded in DeKalb, IL since 1960: the highest and lowest reading for each calendar date, with the year it happened.
How often is it updated?
The forecast portion refreshes every hour; the climate portion is based on long-term data and stays stable.