Monthly outlook for Mount Prospect, IL: average high 58.5°, average low 43.6°. That is 1.3° above the climate normal for October. Precipitation is expected on 3 days (about 0.8 inches), against a normal of 5 days and 1.6 inches. The warmest day looks like 21 October (71.2°), the coolest 28 October (34.5°).
58.5°/43.6°
Average high / low
+1.3°
Above normal
3 / 5
Wet days / normal
0.8 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
20 October – 29 October
61.5°
57.1°
+2.4°
30 October – 8 November
53.4°
53.2°
+0.1°
9 November – 18 November
at normal
47.7°
—
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).
Wed, 2171° / 43°0
71 °
Mount Prospect, Wednesday, 21 October
Clear. High 71°, low 43°.
Pressure30.27 inHg
Wind3.4 mph W
Humidity55%
Visibility6.2 mi
Dew point48°
Thu, 2267° / 49°0
67 °
Mount Prospect, Thursday, 22 October
Partly cloudy. High 67°, low 49°.
Pressure30.30 inHg
Wind5 mph NE
Humidity68%
Visibility6.2 mi
Dew point56°
Fri, 2364° / 50°0
64 °
Mount Prospect, Friday, 23 October
Clear. High 64°, low 50°.
Pressure30.36 inHg
Wind4 mph SE
Humidity75%
Visibility6.2 mi
Dew point53°
Sat, 2466° / 47°0
66 °
Mount Prospect, Saturday, 24 October
Partly cloudy. High 66°, low 47°.
Pressure30.36 inHg
Wind7.4 mph S
Humidity69%
Visibility6.2 mi
Dew point50°
Sun, 2568° / 53°0
68 °
Mount Prospect, Sunday, 25 October
Overcast. High 68°, low 53°.
Pressure30.36 inHg
Wind7.9 mph SW
Humidity65%
Visibility—
Dew point52°
Mon, 2669° / 43°0.26
69 °
Mount Prospect, Monday, 26 October
Rain. High 69°, low 43°.
Pressure30.03 inHg
Wind12 mph NW
Humidity41%
Visibility—
Dew point43°
Tue, 2747° / 39°0.09
47 °
Mount Prospect, Tuesday, 27 October
Light rain. High 47°, low 39°.
Pressure30.36 inHg
Wind12.4 mph NW
Humidity35%
Visibility—
Dew point19°
Wed, 2847° / 35°0
47 °
Mount Prospect, Wednesday, 28 October
Clear. High 47°, low 35°.
Pressure30.39 inHg
Wind10.1 mph SW
Humidity28%
Visibility—
Dew point13°
Thu, 2950° / 40°0
50 °
Mount Prospect, Thursday, 29 October
Clear. High 50°, low 40°.
Pressure30.06 inHg
Wind11 mph W
Humidity39%
Visibility—
Dew point24°
Fri, 3044° / 35°0
44 °
Mount Prospect, Friday, 30 October
Clear. High 44°, low 35°.
Pressure30.39 inHg
Wind11.5 mph NW
Humidity38%
Visibility—
Dew point18°
Sat, 3149° / 35°0
49 °
Mount Prospect, Saturday, 31 October
Partly cloudy. High 49°, low 35°.
Pressure30.24 inHg
Wind11 mph SW
Humidity33%
Visibility—
Dew point18°
Sun, 0150° / 44°0
50 °
Mount Prospect, Sunday, 1 November
Overcast. High 50°, low 44°.
Pressure30.09 inHg
Wind9 mph SW
Humidity81%
Visibility—
Dew point42°
Mon, 0259° / 42°0
59 °
Mount Prospect, Monday, 2 November
Clear. High 59°, low 42°.
Pressure30.30 inHg
Wind6.1 mph SW
Humidity52%
Visibility—
Dew point37°
Tue, 0361° / 48°0
61 °
Mount Prospect, Tuesday, 3 November
Overcast. High 61°, low 48°.
Pressure30.21 inHg
Wind10.6 mph S
Humidity41%
Visibility—
Dew point34°
Wed, 0458° / 52°0.43
58 °
Mount Prospect, Wednesday, 4 November
Rain. High 58°, low 52°.
Pressure29.91 inHg
Wind11.2 mph S
Humidity92%
Visibility—
Dew point50°
From day 17 onward the outlook is built from 60-year climate statistics
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)
Sat, 1447° / 35°0.07
47 °
Mount Prospect, Saturday, 14 November
Climate normal for this date — 60-year average.
Average high47°
Average low35°
Average precipitation0.07 in
Chance of precipitation33%
Record high68° (1971)
Record low15° (1986)
Sun, 1547° / 36°0.09
47 °
Mount Prospect, Sunday, 15 November
Climate normal for this date — 60-year average.
Average high47°
Average low36°
Average precipitation0.09 in
Chance of precipitation28%
Record high69° (2025)
Record low19° (2019)
Mon, 1647° / 35°0.05
47 °
Mount Prospect, Monday, 16 November
Climate normal for this date — 60-year average.
Average high47°
Average low35°
Average precipitation0.05 in
Chance of precipitation23%
Record high62° (2023)
Record low22° (1997)
Tue, 1747° / 36°0.09
47 °
Mount Prospect, Tuesday, 17 November
Climate normal for this date — 60-year average.
Average high47°
Average low36°
Average precipitation0.09 in
Chance of precipitation32%
Record high68° (2016)
Record low16° (2014)
Wed, 1847° / 36°0.13
47 °
Mount Prospect, Wednesday, 18 November
Climate normal for this date — 60-year average.
Average high47°
Average low36°
Average precipitation0.13 in
Chance of precipitation28%
Record high66° (2016)
Record low12° (2014)
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.