Monthly outlook for Mount Prospect, IL: average high 58.5°, average low 45.8°. That is 0.4° above the climate normal for October. Precipitation is expected on 4 days (about 0.6 inches), against a normal of 5 days and 1.5 inches. The warmest day looks like 23 October (71.1°), the coolest 30 October (33.4°).
58.5°/45.8°
Average high / low
+0.4°
Above normal
4 / 5
Wet days / normal
0.6 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
15 October – 24 October
63.7°
58.9°
+2.6°
25 October – 3 November
49.9°
55.1°
-2.9°
4 November – 13 November
at normal
50°
—
October records over 66 years
88.2°3 October 2025All-time high
26.2°31 October 2023All-time low
Climate normals and records are computed from the nearest reference point — Park Ridge (6 mi).
Fri, 1659° / 45°0.05
59 °
Mount Prospect, Friday, 16 October
Light rain. High 59°, low 45°.
Pressure30.00 inHg
Wind14.4 mph NW
Humidity72%
Visibility6.2 mi
Dew point44°
Sat, 1755° / 38°0
55 °
Mount Prospect, Saturday, 17 October
Clear. High 55°, low 38°.
Pressure30.53 inHg
Wind5 mph W
Humidity48%
Visibility6.2 mi
Dew point33°
Sun, 1860° / 42°0
60 °
Mount Prospect, Sunday, 18 October
Clear. High 60°, low 42°.
Pressure30.45 inHg
Wind11.9 mph SW
Humidity55%
Visibility6.2 mi
Dew point40°
Mon, 1962° / 42°0
62 °
Mount Prospect, Monday, 19 October
Partly cloudy. High 62°, low 42°.
Pressure30.39 inHg
Wind8.4 mph SW
Humidity53%
Visibility—
Dew point41°
Tue, 2064° / 46°0
64 °
Mount Prospect, Tuesday, 20 October
Partly cloudy. High 64°, low 46°.
Pressure30.33 inHg
Wind4 mph E
Humidity48%
Visibility—
Dew point42°
Wed, 2167° / 54°0
67 °
Mount Prospect, Wednesday, 21 October
Clear. High 67°, low 54°.
Pressure30.36 inHg
Wind6.2 mph E
Humidity36%
Visibility—
Dew point37°
Thu, 2268° / 54°0
68 °
Mount Prospect, Thursday, 22 October
Overcast. High 68°, low 54°.
Pressure30.27 inHg
Wind5.8 mph S
Humidity36%
Visibility—
Dew point38°
Fri, 2371° / 56°0
71 °
Mount Prospect, Friday, 23 October
Overcast. High 71°, low 56°.
Pressure30.18 inHg
Wind9.4 mph SE
Humidity32%
Visibility—
Dew point37°
Sat, 2465° / 57°0.09
65 °
Mount Prospect, Saturday, 24 October
Light rain. High 65°, low 57°.
Pressure30.15 inHg
Wind10 mph S
Humidity65%
Visibility—
Dew point50°
Sun, 2557° / 48°0.04
57 °
Mount Prospect, Sunday, 25 October
Light rain. High 57°, low 48°.
Pressure30.12 inHg
Wind11 mph W
Humidity59%
Visibility—
Dew point39°
Mon, 2650° / 40°0
50 °
Mount Prospect, Monday, 26 October
Clear. High 50°, low 40°.
Pressure30.30 inHg
Wind11.5 mph W
Humidity35%
Visibility—
Dew point21°
Tue, 2746° / 40°0
46 °
Mount Prospect, Tuesday, 27 October
Overcast. High 46°, low 40°.
Pressure30.24 inHg
Wind10.2 mph W
Humidity26%
Visibility—
Dew point12°
Wed, 2856° / 37°0
56 °
Mount Prospect, Wednesday, 28 October
Overcast. High 56°, low 37°.
Pressure30.06 inHg
Wind13 mph SW
Humidity43%
Visibility—
Dew point28°
Thu, 2949° / 43°0.12
49 °
Mount Prospect, Thursday, 29 October
Light rain. High 49°, low 43°.
Pressure30.09 inHg
Wind6.7 mph NW
Humidity44%
Visibility—
Dew point26°
Fri, 3042° / 33°0
42 °
Mount Prospect, Friday, 30 October
Clear. High 42°, low 33°.
Pressure30.45 inHg
Wind12.2 mph N
Humidity30%
Visibility—
Dew point11°
From day 17 onward the outlook is built from 60-year climate statistics
Sat, 3156° / 44°0.14
56 °
Mount Prospect, Saturday, 31 October
Climate normal for this date — 60-year average.
Average high56°
Average low44°
Average precipitation0.14 in
Chance of precipitation40%
Record high72° (1974)
Record low26° (2023)
Sun, 0155° / 43°0.16
55 °
Mount Prospect, Sunday, 1 November
Climate normal for this date — 60-year average.
Average high55°
Average low43°
Average precipitation0.16 in
Chance of precipitation43%
Record high72° (2016)
Record low18° (2019)
Mon, 0254° / 42°0.12
54 °
Mount Prospect, Monday, 2 November
Climate normal for this date — 60-year average.
Average high54°
Average low42°
Average precipitation0.12 in
Chance of precipitation38%
Record high73° (1961)
Record low24° (1991)
Tue, 0353° / 41°0.06
53 °
Mount Prospect, Tuesday, 3 November
Climate normal for this date — 60-year average.
Average high53°
Average low41°
Average precipitation0.06 in
Chance of precipitation22%
Record high71° (1987)
Record low18° (1991)
Wed, 0452° / 42°0.09
52 °
Mount Prospect, Wednesday, 4 November
Climate normal for this date — 60-year average.
Average high52°
Average low42°
Average precipitation0.09 in
Chance of precipitation27%
Record high70° (2022)
Record low17° (1991)
Thu, 0553° / 41°0.13
53 °
Mount Prospect, Thursday, 5 November
Climate normal for this date — 60-year average.
Average high53°
Average low41°
Average precipitation0.13 in
Chance of precipitation33%
Record high73° (1978)
Record low20° (1991)
Fri, 0652° / 39°0.07
52 °
Mount Prospect, Friday, 6 November
Climate normal for this date — 60-year average.
Average high52°
Average low39°
Average precipitation0.07 in
Chance of precipitation30%
Record high71° (1975)
Record low24° (1991)
Sat, 0751° / 39°0.05
51 °
Mount Prospect, Saturday, 7 November
Climate normal for this date — 60-year average.
Average high51°
Average low39°
Average precipitation0.05 in
Chance of precipitation22%
Record high69° (2020)
Record low20° (1991)
Sun, 0851° / 39°0.05
51 °
Mount Prospect, Sunday, 8 November
Climate normal for this date — 60-year average.
Average high51°
Average low39°
Average precipitation0.05 in
Chance of precipitation18%
Record high74° (2020)
Record low17° (1991)
Mon, 0951° / 39°0.12
51 °
Mount Prospect, Monday, 9 November
Climate normal for this date — 60-year average.
Average high51°
Average low39°
Average precipitation0.12 in
Chance of precipitation38%
Record high72° (2020)
Record low21° (1991)
Tue, 1050° / 39°0.11
50 °
Mount Prospect, Tuesday, 10 November
Climate normal for this date — 60-year average.
Average high50°
Average low39°
Average precipitation0.11 in
Chance of precipitation33%
Record high73° (2020)
Record low18° (2017)
Wed, 1148° / 36°0.08
48 °
Mount Prospect, Wednesday, 11 November
Climate normal for this date — 60-year average.
Average high48°
Average low36°
Average precipitation0.08 in
Chance of precipitation32%
Record high69° (1964)
Record low15° (2019)
Thu, 1246° / 35°0.06
46 °
Mount Prospect, Thursday, 12 November
Climate normal for this date — 60-year average.
Average high46°
Average low35°
Average precipitation0.06 in
Chance of precipitation23%
Record high66° (1964)
Record low3° (2019)
Fri, 1346° / 35°0.05
46 °
Mount Prospect, Friday, 13 November
Climate normal for this date — 60-year average.
Average high46°
Average low35°
Average precipitation0.05 in
Chance of precipitation18%
Record high68° (1999)
Record low1° (2019)
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 Mount Prospect, 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 Mount Prospect, 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.