As of 06:21 CDT

Weather in Lemont, IL

66°

Lemont, Sunday, 9 August, 06:21

Mostly clear. Feels like 66°. High 85°, low 64°.

Pressure30.00 inHg

Wind2 mph SE

Humidity93%

Visibility6.2 mi

Dew point63°

See detailed hourly forecast

Monthly outlook for Lemont, IL: average high 84.1°, average low 68.3°. That is 2.3° above the climate normal for August. Precipitation is expected on 6 days (about 1.3 inches), against a normal of 6 days and 1.9 inches. The warmest day looks like 23 August (93.6°), the coolest 14 August (61.7°).

84.1°/68.3°

Average high / low

+2.3°

Above normal

6 / 6

Wet days / normal

1.3 in

Precipitation this month

Ten-day blocks vs climate normal

Period	Forecast high	Normal	Difference
9 August – 18 August	81°	80°	+0.6°
19 August – 28 August	89.1°	80°	+5.1°
29 August – 7 September	at normal	78.3°	—

August records over 66 years

97°24 August 2023All-time high

46.8°29 August 1965All-time low

Climate normals and records are computed from the nearest reference point — Orland Hills (9 mi).

Mon, 1090° / 72°

0.39

90 °

Lemont, Monday, 10 August

Rain. High 90°, low 72°.

Pressure29.88 inHg

Wind5.5 mph NW

Humidity68%

Visibility6.2 mi

Dew point74°

Tue, 1181° / 70°

0.15

81 °

Lemont, Tuesday, 11 August

Rain. High 81°, low 70°.

Pressure29.85 inHg

Wind6.6 mph W

Humidity73%

Visibility6.2 mi

Dew point71°

Wed, 1285° / 70°

0.04

85 °

Lemont, Wednesday, 12 August

Light rain. High 85°, low 70°.

Pressure29.85 inHg

Wind5.5 mph W

Humidity65%

Visibility6.2 mi

Dew point69°

Thu, 1377° / 66°

0.03

77 °

Lemont, Thursday, 13 August

Light rain. High 77°, low 66°.

Pressure30.00 inHg

Wind8.7 mph E

Humidity52%

Visibility—

Dew point57°

Fri, 1476° / 62°

76 °

Lemont, Friday, 14 August

Overcast. High 76°, low 62°.

Pressure30.15 inHg

Wind9 mph E

Humidity42%

Visibility—

Dew point49°

Sat, 1577° / 63°

0.03

77 °

Lemont, Saturday, 15 August

Light rain. High 77°, low 63°.

Pressure30.24 inHg

Wind8.7 mph S

Humidity52%

Visibility—

Dew point55°

Sun, 1678° / 64°

0.02

78 °

Lemont, Sunday, 16 August

Light rain. High 78°, low 64°.

Pressure30.09 inHg

Wind5.9 mph SE

Humidity64%

Visibility—

Dew point63°

Mon, 1782° / 67°

0.02

82 °

Lemont, Monday, 17 August

Light rain. High 82°, low 67°.

Pressure30.06 inHg

Wind7 mph E

Humidity58%

Visibility—

Dew point64°

Tue, 1879° / 66°

79 °

Lemont, Tuesday, 18 August

Overcast. High 79°, low 66°.

Pressure30.03 inHg

Wind5.4 mph SW

Humidity79%

Visibility—

Dew point66°

Wed, 1986° / 68°

0.07

86 °

Lemont, Wednesday, 19 August

Light rain. High 86°, low 68°.

Pressure29.91 inHg

Wind14.7 mph S

Humidity63%

Visibility—

Dew point68°

Thu, 2087° / 73°

87 °

Lemont, Thursday, 20 August

Overcast. High 87°, low 73°.

Pressure29.77 inHg

Wind7.3 mph S

Humidity60%

Visibility—

Dew point70°

Fri, 2188° / 74°

88 °

Lemont, Friday, 21 August

Clear. High 88°, low 74°.

Pressure29.91 inHg

Wind13.4 mph NE

Humidity44%

Visibility—

Dew point62°

Sat, 2293° / 71°

93 °

Lemont, Saturday, 22 August

Clear. High 93°, low 71°.

Pressure29.85 inHg

Wind9.9 mph S

Humidity60%

Visibility—

Dew point72°

Sun, 2394° / 73°

0.01

94 °

Lemont, Sunday, 23 August

Light rain. High 94°, low 73°.

Pressure29.83 inHg

Wind9.4 mph NE

Humidity43%

Visibility—

Dew point66°

Mon, 2488° / 70°

0.14

88 °

Lemont, Monday, 24 August

Rain. High 88°, low 70°.

Pressure30.03 inHg

Wind8 mph NE

Humidity57%

Visibility—

Dew point67°

From day 17 onward the outlook is built from 60-year climate statistics

Tue, 2580° / 65°

0.09

80 °

Lemont, Tuesday, 25 August

Climate normal for this date — 60-year average.

Average high80°

Average low65°

Average precipitation0.09 in

Chance of precipitation28%

Record high91° (2003)

Record low51° (2017)

Wed, 2681° / 66°

0.15

81 °

Lemont, Wednesday, 26 August

Climate normal for this date — 60-year average.

Average high81°

Average low66°

Average precipitation0.15 in

Chance of precipitation40%

Record high93° (2024)

Record low53° (1964)

Thu, 2781° / 66°

0.12

81 °

Lemont, Thursday, 27 August

Climate normal for this date — 60-year average.

Average high81°

Average low66°

Average precipitation0.12 in

Chance of precipitation33%

Record high95° (2024)

Record low54° (2025)

Fri, 2880° / 65°

0.15

80 °

Lemont, Friday, 28 August

Climate normal for this date — 60-year average.

Average high80°

Average low65°

Average precipitation0.15 in

Chance of precipitation35%

Record high92° (1984)

Record low50° (1986)

Sat, 2980° / 65°

0.13

80 °

Lemont, Saturday, 29 August

Climate normal for this date — 60-year average.

Average high80°

Average low65°

Average precipitation0.13 in

Chance of precipitation37%

Record high93° (1984)

Record low47° (1965)

Sun, 3079° / 64°

0.09

79 °

Lemont, Sunday, 30 August

Climate normal for this date — 60-year average.

Average high79°

Average low64°

Average precipitation0.09 in

Chance of precipitation32%

Record high92° (2013)

Record low51° (1986)

Mon, 3179° / 64°

0.06

79 °

Lemont, Monday, 31 August

Climate normal for this date — 60-year average.

Average high79°

Average low64°

Average precipitation0.06 in

Chance of precipitation23%

Record high89° (2012)

Record low53° (2023)

Tue, 0179° / 63°

0.13

79 °

Lemont, Tuesday, 1 September

Climate normal for this date — 60-year average.

Average high79°

Average low63°

Average precipitation0.13 in

Chance of precipitation30%

Record high95° (2011)

Record low51° (2009)

Wed, 0279° / 64°

0.07

79 °

Lemont, Wednesday, 2 September

Climate normal for this date — 60-year average.

Average high79°

Average low64°

Average precipitation0.07 in

Chance of precipitation27%

Record high92° (2008)

Record low49° (2017)

Thu, 0379° / 64°

0.07

79 °

Lemont, Thursday, 3 September

Climate normal for this date — 60-year average.

Average high79°

Average low64°

Average precipitation0.07 in

Chance of precipitation28%

Record high92° (2023)

Record low51° (1974)

Fri, 0477° / 63°

0.09

77 °

Lemont, Friday, 4 September

Climate normal for this date — 60-year average.

Average high77°

Average low63°

Average precipitation0.09 in

Chance of precipitation32%

Record high90° (2023)

Record low50° (2025)

Sat, 0578° / 62°

0.07

78 °

Lemont, Saturday, 5 September

Climate normal for this date — 60-year average.

Average high78°

Average low62°

Average precipitation0.07 in

Chance of precipitation23%

Record high89° (2023)

Record low51° (1974)

Sun, 0677° / 62°

0.11

77 °

Lemont, Sunday, 6 September

Climate normal for this date — 60-year average.

Average high77°

Average low62°

Average precipitation0.11 in

Chance of precipitation42%

Record high91° (1990)

Record low49° (1962)

Mon, 0777° / 62°

0.15

77 °

Lemont, Monday, 7 September

Climate normal for this date — 60-year average.

Average high77°

Average low62°

Average precipitation0.15 in

Chance of precipitation30%

Record high92° (1960)

Record low48° (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 Lemont, 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 Lemont, 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.