Monthly outlook for Northlake, IL: average high 80.4°, average low 66.5°. That is 0.1° above the climate normal for August. Precipitation is expected on 6 days (about 2.2 inches), against a normal of 6 days and 1.9 inches. The warmest day looks like 12 August (86.3°), the coolest 23 August (58.6°).
80.4°/66.5°
Average high / low
+0.1°
Above normal
6 / 6
Wet days / normal
2.2 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
8 August – 17 August
81.5°
80.5°
+0.6°
18 August – 27 August
78.5°
80.3°
-1°
28 August – 6 September
at normal
78.8°
—
August records over 66 years
99.3°24 August 2023All-time high
48°29 August 1965All-time low
Climate normals and records are computed from the nearest reference point — Stone Park (1 mi).
Sun, 0984° / 65°1.34
84 °
Northlake, Sunday, 9 August
Heavy rain. High 84°, low 65°.
Pressure29.85 inHg
Wind7.2 mph NE
Humidity96%
Visibility6.2 mi
Dew point66°
Mon, 1085° / 72°0.07
85 °
Northlake, Monday, 10 August
Rain. High 85°, low 72°.
Pressure29.88 inHg
Wind3.9 mph SE
Humidity68%
Visibility6.2 mi
Dew point68°
Tue, 1185° / 72°0.22
85 °
Northlake, Tuesday, 11 August
Rain. High 85°, low 72°.
Pressure29.80 inHg
Wind9 mph W
Humidity58%
Visibility6.2 mi
Dew point70°
Wed, 1286° / 69°0.02
86 °
Northlake, Wednesday, 12 August
Light rain. High 86°, low 69°.
Pressure29.85 inHg
Wind3.5 mph NE
Humidity61%
Visibility6.2 mi
Dew point64°
Thu, 1374° / 66°0.06
74 °
Northlake, Thursday, 13 August
Light rain. High 74°, low 66°.
Pressure29.94 inHg
Wind10.1 mph E
Humidity59%
Visibility—
Dew point58°
Fri, 1476° / 62°0
76 °
Northlake, Friday, 14 August
Clear. High 76°, low 62°.
Pressure30.18 inHg
Wind9.2 mph NE
Humidity37%
Visibility—
Dew point47°
Sat, 1579° / 61°0
79 °
Northlake, Saturday, 15 August
Overcast. High 79°, low 61°.
Pressure30.30 inHg
Wind5.4 mph SW
Humidity36%
Visibility—
Dew point46°
Sun, 1681° / 62°0
81 °
Northlake, Sunday, 16 August
Partly cloudy. High 81°, low 62°.
Pressure30.18 inHg
Wind9.3 mph SW
Humidity41%
Visibility—
Dew point51°
Mon, 1782° / 69°0.04
82 °
Northlake, Monday, 17 August
Light rain. High 82°, low 69°.
Pressure30.00 inHg
Wind4.9 mph S
Humidity79%
Visibility—
Dew point66°
Tue, 1884° / 71°0.01
84 °
Northlake, Tuesday, 18 August
Light rain. High 84°, low 71°.
Pressure30.00 inHg
Wind8.6 mph NE
Humidity48%
Visibility—
Dew point61°
Wed, 1986° / 69°0.39
86 °
Northlake, Wednesday, 19 August
Rain. High 86°, low 69°.
Pressure29.91 inHg
Wind8 mph SW
Humidity53%
Visibility—
Dew point65°
Thu, 2077° / 70°0.01
77 °
Northlake, Thursday, 20 August
Light rain. High 77°, low 70°.
Pressure29.88 inHg
Wind7.7 mph NE
Humidity63%
Visibility—
Dew point62°
Fri, 2181° / 66°0
81 °
Northlake, Friday, 21 August
Partly cloudy. High 81°, low 66°.
Pressure29.97 inHg
Wind8.6 mph NE
Humidity48%
Visibility—
Dew point57°
Sat, 2275° / 62°0.01
75 °
Northlake, Saturday, 22 August
Light rain. High 75°, low 62°.
Pressure29.94 inHg
Wind12.5 mph NE
Humidity69%
Visibility—
Dew point60°
Sun, 2368° / 59°0
68 °
Northlake, Sunday, 23 August
Clear. High 68°, low 59°.
Pressure30.24 inHg
Wind10.8 mph NE
Humidity40%
Visibility—
Dew point41°
From day 17 onward the outlook is built from 60-year climate statistics
Mon, 2480° / 65°0.13
80 °
Northlake, Monday, 24 August
Climate normal for this date — 60-year average.
Average high80°
Average low65°
Average precipitation0.13 in
Chance of precipitation27%
Record high99° (2023)
Record low54° (1965)
Tue, 2581° / 65°0.07
81 °
Northlake, Tuesday, 25 August
Climate normal for this date — 60-year average.
Average high81°
Average low65°
Average precipitation0.07 in
Chance of precipitation25%
Record high92° (2024)
Record low51° (2017)
Wed, 2681° / 66°0.15
81 °
Northlake, Wednesday, 26 August
Climate normal for this date — 60-year average.
Average high81°
Average low66°
Average precipitation0.15 in
Chance of precipitation32%
Record high96° (2024)
Record low53° (1964)
Thu, 2781° / 67°0.11
81 °
Northlake, Thursday, 27 August
Climate normal for this date — 60-year average.
Average high81°
Average low67°
Average precipitation0.11 in
Chance of precipitation28%
Record high97° (2024)
Record low54° (2025)
Fri, 2880° / 66°0.13
80 °
Northlake, Friday, 28 August
Climate normal for this date — 60-year average.
Average high80°
Average low66°
Average precipitation0.13 in
Chance of precipitation37%
Record high93° (1984)
Record low50° (1986)
Sat, 2980° / 65°0.12
80 °
Northlake, Saturday, 29 August
Climate normal for this date — 60-year average.
Average high80°
Average low65°
Average precipitation0.12 in
Chance of precipitation28%
Record high95° (1984)
Record low48° (1965)
Sun, 3079° / 64°0.13
79 °
Northlake, Sunday, 30 August
Climate normal for this date — 60-year average.
Average high79°
Average low64°
Average precipitation0.13 in
Chance of precipitation28%
Record high94° (2013)
Record low53° (1986)
Mon, 3179° / 64°0.08
79 °
Northlake, Monday, 31 August
Climate normal for this date — 60-year average.
Average high79°
Average low64°
Average precipitation0.08 in
Chance of precipitation18%
Record high91° (2012)
Record low53° (2023)
Tue, 0179° / 64°0.12
79 °
Northlake, Tuesday, 1 September
Climate normal for this date — 60-year average.
Average high79°
Average low64°
Average precipitation0.12 in
Chance of precipitation32%
Record high94° (2011)
Record low51° (2009)
Wed, 0279° / 64°0.04
79 °
Northlake, Wednesday, 2 September
Climate normal for this date — 60-year average.
Average high79°
Average low64°
Average precipitation0.04 in
Chance of precipitation22%
Record high92° (2008)
Record low48° (2017)
Thu, 0379° / 64°0.09
79 °
Northlake, Thursday, 3 September
Climate normal for this date — 60-year average.
Average high79°
Average low64°
Average precipitation0.09 in
Chance of precipitation28%
Record high94° (2023)
Record low51° (1974)
Fri, 0478° / 63°0.09
78 °
Northlake, Friday, 4 September
Climate normal for this date — 60-year average.
Average high78°
Average low63°
Average precipitation0.09 in
Chance of precipitation32%
Record high92° (2023)
Record low49° (2025)
Sat, 0578° / 62°0.08
78 °
Northlake, Saturday, 5 September
Climate normal for this date — 60-year average.
Average high78°
Average low62°
Average precipitation0.08 in
Chance of precipitation23%
Record high90° (2023)
Record low52° (2010)
Sun, 0677° / 63°0.11
77 °
Northlake, Sunday, 6 September
Climate normal for this date — 60-year average.
Average high77°
Average low63°
Average precipitation0.11 in
Chance of precipitation38%
Record high92° (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 Northlake, 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 Northlake, 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.