As of 17:23 CDT

Weather in Grayslake, IL

81°Current weather

Grayslake, Saturday, 8 August, 17:23

Clear. Feels like 82°. High 81°, low 68°.

Pressure29.97 inHg
Wind3 mph N
Humidity52%
Visibility6.2 mi
Dew point62°

Monthly outlook for Grayslake, IL: average high 77.6°, average low 61.9°. That is 0.2° below the climate normal for August. Precipitation is expected on 6 days (about 2.7 inches), against a normal of 6 days and 1.8 inches. The warmest day looks like 11 August (84.8°), the coolest 23 August (51.2°).

77.6°/61.9°
Average high / low
−0.2°
Below normal
6 / 6
Wet days / normal
2.7 in
Precipitation this month

Ten-day blocks vs climate normal

PeriodForecast highNormalDifference
8 August – 17 August79.2°78.1°+0.6°
18 August – 27 August74.9°77.8°-1.6°
28 August – 6 Septemberat normal76.4°

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 (15 mi).

Sun, 0983° / 64°1.24Heavy rain
83 °Heavy rain

Grayslake, Sunday, 9 August

Heavy rain. High 83°, low 64°.

Pressure29.88 inHg
Wind8.6 mph SE
Humidity94%
Visibility6.2 mi
Dew point64°
Mon, 1083° / 70°0.37Heavy rain
83 °Heavy rain

Grayslake, Monday, 10 August

Heavy rain. High 83°, low 70°.

Pressure29.91 inHg
Wind3.8 mph S
Humidity92%
Visibility6.2 mi
Dew point69°
Tue, 1185° / 68°0.56Heavy rain
85 °Heavy rain

Grayslake, Tuesday, 11 August

Heavy rain. High 85°, low 68°.

Pressure29.80 inHg
Wind4.9 mph N
Humidity99%
Visibility1.7 mi
Dew point72°
Wed, 1284° / 65°0Partly cloudy
84 °Partly cloudy

Grayslake, Wednesday, 12 August

Partly cloudy. High 84°, low 65°.

Pressure29.88 inHg
Wind3.9 mph SW
Humidity67%
Visibility6.2 mi
Dew point65°
Thu, 1368° / 58°0.09Light rain
68 °Light rain

Grayslake, Thursday, 13 August

Light rain. High 68°, low 58°.

Pressure29.97 inHg
Wind10.2 mph NE
Humidity80%
Visibility
Dew point60°
Fri, 1473° / 56°0Clear
73 °Clear

Grayslake, Friday, 14 August

Clear. High 73°, low 56°.

Pressure30.18 inHg
Wind7.6 mph NE
Humidity51%
Visibility
Dew point51°
Sat, 1576° / 55°0Overcast
76 °Overcast

Grayslake, Saturday, 15 August

Overcast. High 76°, low 55°.

Pressure30.30 inHg
Wind6 mph SW
Humidity50%
Visibility
Dew point52°
Sun, 1677° / 58°0Partly cloudy
77 °Partly cloudy

Grayslake, Sunday, 16 August

Partly cloudy. High 77°, low 58°.

Pressure30.18 inHg
Wind11.4 mph SW
Humidity53%
Visibility
Dew point56°
Mon, 1781° / 67°0.01Light rain
81 °Light rain

Grayslake, Monday, 17 August

Light rain. High 81°, low 67°.

Pressure30.00 inHg
Wind7.1 mph S
Humidity87%
Visibility
Dew point65°
Tue, 1880° / 65°0.01Light rain
80 °Light rain

Grayslake, Tuesday, 18 August

Light rain. High 80°, low 65°.

Pressure30.03 inHg
Wind8.2 mph NE
Humidity62%
Visibility
Dew point64°
Wed, 1983° / 65°0.3Rain
83 °Rain

Grayslake, Wednesday, 19 August

Rain. High 83°, low 65°.

Pressure29.91 inHg
Wind8.6 mph SW
Humidity61%
Visibility
Dew point65°
Thu, 2076° / 63°0.01Light rain
76 °Light rain

Grayslake, Thursday, 20 August

Light rain. High 76°, low 63°.

Pressure29.91 inHg
Wind9.8 mph NE
Humidity72%
Visibility
Dew point64°
Fri, 2177° / 61°0Overcast
77 °Overcast

Grayslake, Friday, 21 August

Overcast. High 77°, low 61°.

Pressure29.97 inHg
Wind7.9 mph NE
Humidity63%
Visibility
Dew point61°
Sat, 2270° / 57°0.11Light rain
70 °Light rain

Grayslake, Saturday, 22 August

Light rain. High 70°, low 57°.

Pressure30.00 inHg
Wind16 mph NE
Humidity86%
Visibility
Dew point59°
Sun, 2365° / 51°0Clear
65 °Clear

Grayslake, Sunday, 23 August

Clear. High 65°, low 51°.

Pressure30.27 inHg
Wind11.7 mph NE
Humidity53%
Visibility
Dew point46°
From day 17 onward the outlook is built from 60-year climate statistics
Mon, 2478° / 68°0.11Climate normal
78 °Climate normal

Grayslake, 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°0.07Climate normal
78 °Climate normal

Grayslake, 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°0.14Climate normal
79 °Climate normal

Grayslake, 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°0.1Climate normal
78 °Climate normal

Grayslake, 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°0.12Climate normal
78 °Climate normal

Grayslake, 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°0.13Climate normal
78 °Climate normal

Grayslake, 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°0.09Climate normal
77 °Climate normal

Grayslake, 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°0.06Climate normal
76 °Climate normal

Grayslake, 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°0.1Climate normal
76 °Climate normal

Grayslake, 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°0.04Climate normal
77 °Climate normal

Grayslake, 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°0.09Climate normal
76 °Climate normal

Grayslake, 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°0.08Climate normal
75 °Climate normal

Grayslake, 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°0.08Climate normal
75 °Climate normal

Grayslake, 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°0.09Climate normal
75 °Climate normal

Grayslake, 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 Grayslake, 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 Grayslake, 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.