Monthly outlook for Thornton, IL: average high 63°, average low 48.1°. That is 3.1° above the climate normal for October. Precipitation is expected on 6 days (about 2.0 inches), against a normal of 5 days and 1.7 inches. The warmest day looks like 24 October (71.8°), the coolest 18 October (39.7°).
63°/48.1°
Average high / low
+3.1°
Above normal
6 / 5
Wet days / normal
2.0 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
18 October – 27 October
63.7°
58.3°
+3°
28 October – 6 November
61.8°
54.6°
+4°
7 November – 16 November
at normal
49°
—
October records over 66 years
88.5°3 October 2025All-time high
26.2°26 October 1962All-time low
Climate normals and records are computed from the nearest reference point — Calumet Park (7 mi).
Mon, 1963° / 42°0
63 °
Thornton, Monday, 19 October
Clear. High 63°, low 42°.
Pressure30.42 inHg
Wind1.7 mph SW
Humidity61%
Visibility6.2 mi
Dew point46°
Tue, 2064° / 42°0
64 °
Thornton, Tuesday, 20 October
Clear. High 64°, low 42°.
Pressure30.39 inHg
Wind2.1 mph E
Humidity58%
Visibility6.2 mi
Dew point47°
Wed, 2166° / 44°0
66 °
Thornton, Wednesday, 21 October
Clear. High 66°, low 44°.
Pressure30.30 inHg
Wind2 mph SW
Humidity61%
Visibility6.2 mi
Dew point50°
Thu, 2266° / 48°0
66 °
Thornton, Thursday, 22 October
Clear. High 66°, low 48°.
Pressure30.30 inHg
Wind5.6 mph NE
Humidity66%
Visibility—
Dew point51°
Fri, 2362° / 47°0
62 °
Thornton, Friday, 23 October
Partly cloudy. High 62°, low 47°.
Pressure30.36 inHg
Wind6.9 mph SE
Humidity65%
Visibility—
Dew point48°
Sat, 2472° / 52°0
72 °
Thornton, Saturday, 24 October
Overcast. High 72°, low 52°.
Pressure30.30 inHg
Wind13.6 mph S
Humidity43%
Visibility—
Dew point44°
Sun, 2565° / 53°0.14
65 °
Thornton, Sunday, 25 October
Light rain. High 65°, low 53°.
Pressure30.42 inHg
Wind8.7 mph N
Humidity29%
Visibility—
Dew point27°
Mon, 2653° / 48°0.09
53 °
Thornton, Monday, 26 October
Light rain. High 53°, low 48°.
Pressure30.36 inHg
Wind5.1 mph SE
Humidity64%
Visibility—
Dew point38°
Tue, 2765° / 52°0
65 °
Thornton, Tuesday, 27 October
Overcast. High 65°, low 52°.
Pressure30.30 inHg
Wind6.3 mph SE
Humidity61%
Visibility—
Dew point46°
Wed, 2863° / 58°0.11
63 °
Thornton, Wednesday, 28 October
Light rain. High 63°, low 58°.
Pressure30.00 inHg
Wind10.6 mph S
Humidity69%
Visibility—
Dew point48°
Thu, 2968° / 59°0.24
68 °
Thornton, Thursday, 29 October
Light rain. High 68°, low 59°.
Pressure29.77 inHg
Wind9.9 mph S
Humidity87%
Visibility—
Dew point60°
Fri, 3070° / 55°0.26
70 °
Thornton, Friday, 30 October
Rain. High 70°, low 55°.
Pressure29.80 inHg
Wind14.4 mph S
Humidity52%
Visibility—
Dew point49°
Sat, 3165° / 48°1.11
65 °
Thornton, Saturday, 31 October
Heavy rain. High 65°, low 48°.
Pressure29.65 inHg
Wind19.7 mph SW
Humidity47%
Visibility—
Dew point37°
Sun, 0149° / 42°0
49 °
Thornton, Sunday, 1 November
Overcast. High 49°, low 42°.
Pressure30.18 inHg
Wind17.4 mph W
Humidity54%
Visibility—
Dew point31°
Mon, 0256° / 40°0
56 °
Thornton, Monday, 2 November
Partly cloudy. High 56°, low 40°.
Pressure30.42 inHg
Wind6.6 mph S
Humidity36%
Visibility—
Dew point26°
From day 17 onward the outlook is built from 60-year climate statistics
Tue, 0353° / 41°0.07
53 °
Thornton, Tuesday, 3 November
Climate normal for this date — 60-year average.
Average high53°
Average low41°
Average precipitation0.07 in
Chance of precipitation25%
Record high72° (1987)
Record low19° (1991)
Wed, 0453° / 43°0.09
53 °
Thornton, Wednesday, 4 November
Climate normal for this date — 60-year average.
Average high53°
Average low43°
Average precipitation0.09 in
Chance of precipitation27%
Record high71° (2015)
Record low19° (1991)
Thu, 0553° / 41°0.13
53 °
Thornton, Thursday, 5 November
Climate normal for this date — 60-year average.
Average high53°
Average low41°
Average precipitation0.13 in
Chance of precipitation32%
Record high74° (1978)
Record low20° (1991)
Fri, 0653° / 40°0.07
53 °
Thornton, Friday, 6 November
Climate normal for this date — 60-year average.
Average high53°
Average low40°
Average precipitation0.07 in
Chance of precipitation30%
Record high72° (1975)
Record low25° (1991)
Sat, 0752° / 40°0.06
52 °
Thornton, Saturday, 7 November
Climate normal for this date — 60-year average.
Average high52°
Average low40°
Average precipitation0.06 in
Chance of precipitation20%
Record high70° (2020)
Record low22° (1991)
Sun, 0851° / 39°0.06
51 °
Thornton, Sunday, 8 November
Climate normal for this date — 60-year average.
Average high51°
Average low39°
Average precipitation0.06 in
Chance of precipitation20%
Record high74° (2020)
Record low17° (1991)
Mon, 0952° / 40°0.13
52 °
Thornton, Monday, 9 November
Climate normal for this date — 60-year average.
Average high52°
Average low40°
Average precipitation0.13 in
Chance of precipitation35%
Record high72° (2020)
Record low20° (1991)
Tue, 1051° / 39°0.13
51 °
Thornton, Tuesday, 10 November
Climate normal for this date — 60-year average.
Average high51°
Average low39°
Average precipitation0.13 in
Chance of precipitation40%
Record high73° (2020)
Record low18° (2018)
Wed, 1148° / 37°0.08
48 °
Thornton, Wednesday, 11 November
Climate normal for this date — 60-year average.
Average high48°
Average low37°
Average precipitation0.08 in
Chance of precipitation32%
Record high70° (1964)
Record low19° (2019)
Thu, 1247° / 35°0.06
47 °
Thornton, Thursday, 12 November
Climate normal for this date — 60-year average.
Average high47°
Average low35°
Average precipitation0.06 in
Chance of precipitation23%
Record high68° (1964)
Record low6° (2019)
Fri, 1347° / 35°0.05
47 °
Thornton, Friday, 13 November
Climate normal for this date — 60-year average.
Average high47°
Average low35°
Average precipitation0.05 in
Chance of precipitation20%
Record high68° (1999)
Record low3° (2019)
Sat, 1448° / 35°0.07
48 °
Thornton, Saturday, 14 November
Climate normal for this date — 60-year average.
Average high48°
Average low35°
Average precipitation0.07 in
Chance of precipitation33%
Record high69° (1971)
Record low15° (1986)
Sun, 1547° / 36°0.1
47 °
Thornton, Sunday, 15 November
Climate normal for this date — 60-year average.
Average high47°
Average low36°
Average precipitation0.1 in
Chance of precipitation32%
Record high67° (2025)
Record low21° (1982)
Mon, 1647° / 35°0.05
47 °
Thornton, Monday, 16 November
Climate normal for this date — 60-year average.
Average high47°
Average low35°
Average precipitation0.05 in
Chance of precipitation25%
Record high63° (2023)
Record low22° (1997)
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 Thornton, 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 Thornton, 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.