Monthly outlook for Lisle, IL: average high 78.4°, average low 64.3°. That is 1.1° below the climate normal for August. Precipitation is expected on 5 days (about 2.1 inches), against a normal of 6 days and 1.8 inches. The warmest day looks like 11 August (85°), the coolest 23 August (55.8°).
78.4°/64.3°
Average high / low
−1.1°
Below normal
5 / 6
Wet days / normal
2.1 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
8 August – 17 August
78.9°
80.5°
-0.9°
18 August – 27 August
77.5°
80.4°
-1.6°
28 August – 6 September
at normal
78.9°
—
August records over 66 years
98.1°24 August 2023All-time high
44.2°29 August 1986All-time low
Climate normals and records are computed from the nearest reference point — Naperville (5 mi).
Sun, 0984° / 64°1.45
84 °
Lisle, Sunday, 9 August
Heavy rain. High 84°, low 64°.
Pressure29.88 inHg
Wind3 mph NE
Humidity97%
Visibility1.4 mi
Dew point71°
Mon, 1082° / 71°0.06
82 °
Lisle, Monday, 10 August
Rain. High 82°, low 71°.
Pressure29.91 inHg
Wind6.8 mph SE
Humidity68%
Visibility6.2 mi
Dew point70°
Tue, 1185° / 72°0.13
85 °
Lisle, Tuesday, 11 August
Light rain. High 85°, low 72°.
Pressure29.80 inHg
Wind9.9 mph W
Humidity79%
Visibility6.2 mi
Dew point72°
Wed, 1281° / 68°0.02
81 °
Lisle, Wednesday, 12 August
Light rain. High 81°, low 68°.
Pressure29.85 inHg
Wind3.6 mph NW
Humidity84%
Visibility6.2 mi
Dew point68°
Thu, 1372° / 63°0.05
72 °
Lisle, Thursday, 13 August
Light rain. High 72°, low 63°.
Pressure29.94 inHg
Wind12.3 mph E
Humidity67%
Visibility—
Dew point60°
Fri, 1475° / 59°0
75 °
Lisle, Friday, 14 August
Clear. High 75°, low 59°.
Pressure30.18 inHg
Wind7.4 mph N
Humidity46%
Visibility—
Dew point51°
Sat, 1574° / 57°0
74 °
Lisle, Saturday, 15 August
Overcast. High 74°, low 57°.
Pressure30.33 inHg
Wind6.1 mph S
Humidity55%
Visibility—
Dew point54°
Sun, 1676° / 58°0
76 °
Lisle, Sunday, 16 August
Partly cloudy. High 76°, low 58°.
Pressure30.21 inHg
Wind10 mph S
Humidity61%
Visibility—
Dew point58°
Mon, 1776° / 66°0.03
76 °
Lisle, Monday, 17 August
Light rain. High 76°, low 66°.
Pressure30.00 inHg
Wind5.7 mph S
Humidity83%
Visibility—
Dew point67°
Tue, 1884° / 69°0
84 °
Lisle, Tuesday, 18 August
Partly cloudy. High 84°, low 69°.
Pressure30.00 inHg
Wind8 mph NE
Humidity54%
Visibility—
Dew point64°
Wed, 1982° / 65°0.34
82 °
Lisle, Wednesday, 19 August
Rain. High 82°, low 65°.
Pressure29.91 inHg
Wind9.4 mph SW
Humidity69%
Visibility—
Dew point69°
Thu, 2078° / 67°0.03
78 °
Lisle, Thursday, 20 August
Light rain. High 78°, low 67°.
Pressure29.88 inHg
Wind9.1 mph N
Humidity66%
Visibility—
Dew point64°
Fri, 2181° / 64°0.02
81 °
Lisle, Friday, 21 August
Light rain. High 81°, low 64°.
Pressure29.94 inHg
Wind6.2 mph NE
Humidity52%
Visibility—
Dew point59°
Sat, 2273° / 60°0.02
73 °
Lisle, Saturday, 22 August
Light rain. High 73°, low 60°.
Pressure29.94 inHg
Wind15.1 mph NE
Humidity75%
Visibility—
Dew point63°
Sun, 2367° / 56°0
67 °
Lisle, Sunday, 23 August
Clear. High 67°, low 56°.
Pressure30.24 inHg
Wind12.1 mph NE
Humidity44%
Visibility—
Dew point43°
From day 17 onward the outlook is built from 60-year climate statistics
Mon, 2481° / 64°0.13
81 °
Lisle, Monday, 24 August
Climate normal for this date — 60-year average.
Average high81°
Average low64°
Average precipitation0.13 in
Chance of precipitation33%
Record high98° (2023)
Record low52° (1967)
Tue, 2581° / 64°0.09
81 °
Lisle, Tuesday, 25 August
Climate normal for this date — 60-year average.
Average high81°
Average low64°
Average precipitation0.09 in
Chance of precipitation28%
Record high92° (2003)
Record low52° (1977)
Wed, 2681° / 65°0.19
81 °
Lisle, Wednesday, 26 August
Climate normal for this date — 60-year average.
Average high81°
Average low65°
Average precipitation0.19 in
Chance of precipitation35%
Record high94° (2024)
Record low50° (1964)
Thu, 2781° / 65°0.13
81 °
Lisle, Thursday, 27 August
Climate normal for this date — 60-year average.
Average high81°
Average low65°
Average precipitation0.13 in
Chance of precipitation25%
Record high96° (2024)
Record low52° (2025)
Fri, 2880° / 65°0.11
80 °
Lisle, Friday, 28 August
Climate normal for this date — 60-year average.
Average high80°
Average low65°
Average precipitation0.11 in
Chance of precipitation33%
Record high93° (1984)
Record low47° (1986)
Sat, 2980° / 64°0.13
80 °
Lisle, Saturday, 29 August
Climate normal for this date — 60-year average.
Average high80°
Average low64°
Average precipitation0.13 in
Chance of precipitation33%
Record high94° (1984)
Record low44° (1986)
Sun, 3079° / 63°0.08
79 °
Lisle, Sunday, 30 August
Climate normal for this date — 60-year average.
Average high79°
Average low63°
Average precipitation0.08 in
Chance of precipitation30%
Record high93° (2013)
Record low49° (1986)
Mon, 3179° / 63°0.07
79 °
Lisle, Monday, 31 August
Climate normal for this date — 60-year average.
Average high79°
Average low63°
Average precipitation0.07 in
Chance of precipitation18%
Record high89° (2012)
Record low50° (2009)
Tue, 0179° / 62°0.13
79 °
Lisle, Tuesday, 1 September
Climate normal for this date — 60-year average.
Average high79°
Average low62°
Average precipitation0.13 in
Chance of precipitation32%
Record high94° (2011)
Record low47° (2009)
Wed, 0279° / 63°0.05
79 °
Lisle, Wednesday, 2 September
Climate normal for this date — 60-year average.
Average high79°
Average low63°
Average precipitation0.05 in
Chance of precipitation22%
Record high92° (2008)
Record low47° (2017)
Thu, 0379° / 63°0.09
79 °
Lisle, Thursday, 3 September
Climate normal for this date — 60-year average.
Average high79°
Average low63°
Average precipitation0.09 in
Chance of precipitation25%
Record high93° (2023)
Record low47° (1974)
Fri, 0478° / 62°0.1
78 °
Lisle, Friday, 4 September
Climate normal for this date — 60-year average.
Average high78°
Average low62°
Average precipitation0.1 in
Chance of precipitation27%
Record high91° (2023)
Record low46° (1974)
Sat, 0578° / 61°0.07
78 °
Lisle, Saturday, 5 September
Climate normal for this date — 60-year average.
Average high78°
Average low61°
Average precipitation0.07 in
Chance of precipitation22%
Record high89° (1983)
Record low49° (2010)
Sun, 0677° / 61°0.11
77 °
Lisle, Sunday, 6 September
Climate normal for this date — 60-year average.
Average high77°
Average low61°
Average precipitation0.11 in
Chance of precipitation42%
Record high91° (1990)
Record low46° (1988)
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 Lisle, 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 Lisle, 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.