Monthly outlook for Bannockburn, IL: average high 77.9°, average low 65°. That is 0° above the climate normal for August. Precipitation is expected on 3 days (about 2.9 inches), against a normal of 6 days and 1.8 inches. The warmest day looks like 10 August (85.4°), the coolest 20 August (56.9°).
77.9°/65°
Average high / low
+0°
Above normal
3 / 6
Wet days / normal
2.9 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
8 August – 17 August
79.6°
78.1°
+0.8°
18 August – 27 August
75.2°
77.8°
-1.5°
28 August – 6 September
at normal
76.4°
—
August records over 66 years
98.6°24 August 2023All-time high
52.5°22 August 2024All-time low
Climate normals and records are computed from the nearest reference point — Highwood (3 mi).
Sun, 0985° / 64°1.35
85 °
Bannockburn, Sunday, 9 August
Heavy rain. High 85°, low 64°.
Pressure29.94 inHg
Wind9.6 mph SW
Humidity62%
Visibility6.2 mi
Dew point69°
Mon, 1085° / 71°0.95
85 °
Bannockburn, Monday, 10 August
Heavy rain. High 85°, low 71°.
Pressure29.91 inHg
Wind3.3 mph SE
Humidity65%
Visibility6.2 mi
Dew point67°
Tue, 1183° / 70°0.56
83 °
Bannockburn, Tuesday, 11 August
Heavy rain. High 83°, low 70°.
Pressure29.80 inHg
Wind4.8 mph SE
Humidity92%
Visibility6.2 mi
Dew point70°
Wed, 1281° / 68°0
81 °
Bannockburn, Wednesday, 12 August
Overcast. High 81°, low 68°.
Pressure29.85 inHg
Wind2.8 mph NW
Humidity64%
Visibility6.2 mi
Dew point65°
Thu, 1371° / 66°0
71 °
Bannockburn, Thursday, 13 August
Overcast. High 71°, low 66°.
Pressure30.03 inHg
Wind10.3 mph NE
Humidity55%
Visibility—
Dew point53°
Fri, 1476° / 61°0
76 °
Bannockburn, Friday, 14 August
Clear. High 76°, low 61°.
Pressure30.12 inHg
Wind7.9 mph NE
Humidity47%
Visibility—
Dew point53°
Sat, 1576° / 66°0
76 °
Bannockburn, Saturday, 15 August
Overcast. High 76°, low 66°.
Pressure30.27 inHg
Wind7.3 mph E
Humidity43%
Visibility—
Dew point51°
Sun, 1675° / 64°0
75 °
Bannockburn, Sunday, 16 August
Overcast. High 75°, low 64°.
Pressure30.15 inHg
Wind5.7 mph E
Humidity55%
Visibility—
Dew point56°
Mon, 1781° / 66°0.01
81 °
Bannockburn, Monday, 17 August
Light rain. High 81°, low 66°.
Pressure30.03 inHg
Wind4.6 mph W
Humidity55%
Visibility—
Dew point60°
Tue, 1885° / 69°0
85 °
Bannockburn, Tuesday, 18 August
Overcast. High 85°, low 69°.
Pressure29.94 inHg
Wind11 mph SW
Humidity50%
Visibility—
Dew point61°
Wed, 1975° / 64°0
75 °
Bannockburn, Wednesday, 19 August
Light rain. High 75°, low 64°.
Pressure29.91 inHg
Wind16.4 mph NW
Humidity60%
Visibility—
Dew point57°
Thu, 2068° / 57°0
68 °
Bannockburn, Thursday, 20 August
Overcast. High 68°, low 57°.
Pressure30.06 inHg
Wind10.6 mph NW
Humidity52%
Visibility—
Dew point49°
Fri, 2172° / 57°0
72 °
Bannockburn, Friday, 21 August
Clear. High 72°, low 57°.
Pressure30.09 inHg
Wind9 mph NE
Humidity47%
Visibility—
Dew point49°
Sat, 2268° / 62°0.02
68 °
Bannockburn, Saturday, 22 August
Light rain. High 68°, low 62°.
Pressure29.91 inHg
Wind9.7 mph S
Humidity79%
Visibility—
Dew point57°
Sun, 2382° / 66°0
82 °
Bannockburn, Sunday, 23 August
Mostly clear. High 82°, low 66°.
Pressure29.88 inHg
Wind13.9 mph W
Humidity38%
Visibility—
Dew point52°
From day 17 onward the outlook is built from 60-year climate statistics
Mon, 2478° / 68°0.11
78 °
Bannockburn, Monday, 24 August
Climate normal for this date — 60-year average.
Average high78°
Average low68°
Average precipitation0.11 in
Chance of precipitation25%
Record high99° (2023)
Record low58° (2025)
Tue, 2578° / 68°0.07
78 °
Bannockburn, Tuesday, 25 August
Climate normal for this date — 60-year average.
Average high78°
Average low68°
Average precipitation0.07 in
Chance of precipitation25%
Record high91° (2024)
Record low54° (2017)
Wed, 2679° / 68°0.14
79 °
Bannockburn, Wednesday, 26 August
Climate normal for this date — 60-year average.
Average high79°
Average low68°
Average precipitation0.14 in
Chance of precipitation35%
Record high94° (2024)
Record low54° (2025)
Thu, 2778° / 69°0.1
78 °
Bannockburn, Thursday, 27 August
Climate normal for this date — 60-year average.
Average high78°
Average low69°
Average precipitation0.1 in
Chance of precipitation32%
Record high96° (2024)
Record low55° (2025)
Fri, 2878° / 68°0.12
78 °
Bannockburn, Friday, 28 August
Climate normal for this date — 60-year average.
Average high78°
Average low68°
Average precipitation0.12 in
Chance of precipitation35%
Record high92° (2021)
Record low54° (1986)
Sat, 2978° / 68°0.13
78 °
Bannockburn, Saturday, 29 August
Climate normal for this date — 60-year average.
Average high78°
Average low68°
Average precipitation0.13 in
Chance of precipitation28%
Record high89° (1984)
Record low54° (1965)
Sun, 3077° / 67°0.09
77 °
Bannockburn, Sunday, 30 August
Climate normal for this date — 60-year average.
Average high77°
Average low67°
Average precipitation0.09 in
Chance of precipitation27%
Record high91° (2013)
Record low57° (2023)
Mon, 3176° / 67°0.06
76 °
Bannockburn, Monday, 31 August
Climate normal for this date — 60-year average.
Average high76°
Average low67°
Average precipitation0.06 in
Chance of precipitation20%
Record high89° (2012)
Record low56° (2025)
Tue, 0176° / 67°0.1
76 °
Bannockburn, Tuesday, 1 September
Climate normal for this date — 60-year average.
Average high76°
Average low67°
Average precipitation0.1 in
Chance of precipitation28%
Record high89° (1960)
Record low57° (2017)
Wed, 0277° / 67°0.04
77 °
Bannockburn, Wednesday, 2 September
Climate normal for this date — 60-year average.
Average high77°
Average low67°
Average precipitation0.04 in
Chance of precipitation25%
Record high87° (2023)
Record low50° (2017)
Thu, 0376° / 66°0.09
76 °
Bannockburn, Thursday, 3 September
Climate normal for this date — 60-year average.
Average high76°
Average low66°
Average precipitation0.09 in
Chance of precipitation27%
Record high92° (2023)
Record low54° (1974)
Fri, 0475° / 66°0.08
75 °
Bannockburn, Friday, 4 September
Climate normal for this date — 60-year average.
Average high75°
Average low66°
Average precipitation0.08 in
Chance of precipitation30%
Record high91° (2023)
Record low49° (2025)
Sat, 0575° / 65°0.08
75 °
Bannockburn, Saturday, 5 September
Climate normal for this date — 60-year average.
Average high75°
Average low65°
Average precipitation0.08 in
Chance of precipitation25%
Record high89° (2023)
Record low55° (2017)
Sun, 0675° / 65°0.09
75 °
Bannockburn, Sunday, 6 September
Climate normal for this date — 60-year average.
Average high75°
Average low65°
Average precipitation0.09 in
Chance of precipitation33%
Record high90° (1990)
Record low49° (2025)
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 Bannockburn, 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 Bannockburn, 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.