As of 16:36 CDT

Weather in Markham, IL

83°Current weather

Markham, Saturday, 8 August, 16:36

Clear. Feels like 87°. High 83°, low 69°.

Pressure29.97 inHg
Wind8.3 mph W
Humidity64%
Visibility6.2 mi
Dew point69°

Monthly outlook for Markham, IL: average high 79°, average low 65.4°. That is 0.5° below the climate normal for August. Precipitation is expected on 6 days (about 2.6 inches), against a normal of 6 days and 1.9 inches. The warmest day looks like 11 August (86.5°), the coolest 23 August (55.3°).

79°/65.4°
Average high / low
−0.5°
Below normal
6 / 6
Wet days / normal
2.6 in
Precipitation this month

Ten-day blocks vs climate normal

PeriodForecast highNormalDifference
8 August – 17 August79.3°80°-0.4°
18 August – 27 August78.4°79.9°-0.8°
28 August – 6 Septemberat normal78.5°

August records over 66 years

98.1°24 August 2023All-time high
49.1°29 August 1965All-time low

Climate normals and records are computed from the nearest reference point — Blue Island (4 mi).

Sun, 0983° / 66°1.67Heavy rain
83 °Heavy rain

Markham, Sunday, 9 August

Heavy rain. High 83°, low 66°.

Pressure29.91 inHg
Wind7.2 mph SW
Humidity77%
Visibility6.2 mi
Dew point74°
Mon, 1083° / 73°0.09Rain
83 °Rain

Markham, Monday, 10 August

Rain. High 83°, low 73°.

Pressure29.91 inHg
Wind5.3 mph SE
Humidity70%
Visibility6.2 mi
Dew point71°
Tue, 1186° / 73°0.18Light rain
86 °Light rain

Markham, Tuesday, 11 August

Light rain. High 86°, low 73°.

Pressure29.77 inHg
Wind15.1 mph SW
Humidity72%
Visibility6.2 mi
Dew point72°
Wed, 1281° / 70°0.01Light rain
81 °Light rain

Markham, Wednesday, 12 August

Light rain. High 81°, low 70°.

Pressure29.83 inHg
Wind5.9 mph NE
Humidity69%
Visibility6.2 mi
Dew point66°
Thu, 1372° / 64°0.03Light rain
72 °Light rain

Markham, Thursday, 13 August

Light rain. High 72°, low 64°.

Pressure29.94 inHg
Wind10.9 mph NE
Humidity66%
Visibility
Dew point60°
Fri, 1474° / 61°0Clear
74 °Clear

Markham, Friday, 14 August

Clear. High 74°, low 61°.

Pressure30.18 inHg
Wind10.5 mph NE
Humidity47%
Visibility
Dew point51°
Sat, 1576° / 58°0Overcast
76 °Overcast

Markham, Saturday, 15 August

Overcast. High 76°, low 58°.

Pressure30.33 inHg
Wind6 mph S
Humidity48%
Visibility
Dew point52°
Sun, 1678° / 59°0Mostly clear
78 °Mostly clear

Markham, Sunday, 16 August

Mostly clear. High 78°, low 59°.

Pressure30.21 inHg
Wind9.6 mph S
Humidity54%
Visibility
Dew point57°
Mon, 1775° / 68°0.11Light rain
75 °Light rain

Markham, Monday, 17 August

Light rain. High 75°, low 68°.

Pressure30.00 inHg
Wind6.2 mph S
Humidity90%
Visibility
Dew point68°
Tue, 1883° / 69°0Partly cloudy
83 °Partly cloudy

Markham, Tuesday, 18 August

Partly cloudy. High 83°, low 69°.

Pressure30.00 inHg
Wind8.6 mph NE
Humidity54%
Visibility
Dew point64°
Wed, 1984° / 66°0.39Rain
84 °Rain

Markham, Wednesday, 19 August

Rain. High 84°, low 66°.

Pressure29.91 inHg
Wind8.4 mph SW
Humidity62%
Visibility
Dew point67°
Thu, 2080° / 67°0.06Light rain
80 °Light rain

Markham, Thursday, 20 August

Light rain. High 80°, low 67°.

Pressure29.88 inHg
Wind9 mph N
Humidity64%
Visibility
Dew point65°
Fri, 2179° / 66°0Partly cloudy
79 °Partly cloudy

Markham, Friday, 21 August

Partly cloudy. High 79°, low 66°.

Pressure29.97 inHg
Wind9.4 mph NE
Humidity54%
Visibility
Dew point60°
Sat, 2278° / 62°0.02Light rain
78 °Light rain

Markham, Saturday, 22 August

Light rain. High 78°, low 62°.

Pressure29.91 inHg
Wind14.6 mph N
Humidity63%
Visibility
Dew point63°
Sun, 2366° / 55°0Mostly clear
66 °Mostly clear

Markham, Sunday, 23 August

Mostly clear. High 66°, low 55°.

Pressure30.24 inHg
Wind11.8 mph NE
Humidity43%
Visibility
Dew point42°
From day 17 onward the outlook is built from 60-year climate statistics
Mon, 2480° / 66°0.14Climate normal
80 °Climate normal

Markham, Monday, 24 August

Climate normal for this date — 60-year average.

Average high80°
Average low66°
Average precipitation0.14 in
Chance of precipitation28%
Record high98° (2023)
Record low56° (1966)
Tue, 2580° / 66°0.07Climate normal
80 °Climate normal

Markham, Tuesday, 25 August

Climate normal for this date — 60-year average.

Average high80°
Average low66°
Average precipitation0.07 in
Chance of precipitation27%
Record high92° (2021)
Record low53° (2017)
Wed, 2681° / 67°0.17Climate normal
81 °Climate normal

Markham, Wednesday, 26 August

Climate normal for this date — 60-year average.

Average high81°
Average low67°
Average precipitation0.17 in
Chance of precipitation35%
Record high94° (2024)
Record low54° (2025)
Thu, 2780° / 67°0.14Climate normal
80 °Climate normal

Markham, Thursday, 27 August

Climate normal for this date — 60-year average.

Average high80°
Average low67°
Average precipitation0.14 in
Chance of precipitation37%
Record high96° (2024)
Record low54° (2025)
Fri, 2880° / 67°0.15Climate normal
80 °Climate normal

Markham, Friday, 28 August

Climate normal for this date — 60-year average.

Average high80°
Average low67°
Average precipitation0.15 in
Chance of precipitation37%
Record high92° (1984)
Record low51° (1986)
Sat, 2980° / 66°0.1Climate normal
80 °Climate normal

Markham, Saturday, 29 August

Climate normal for this date — 60-year average.

Average high80°
Average low66°
Average precipitation0.1 in
Chance of precipitation28%
Record high92° (1984)
Record low49° (1965)
Sun, 3079° / 65°0.09Climate normal
79 °Climate normal

Markham, Sunday, 30 August

Climate normal for this date — 60-year average.

Average high79°
Average low65°
Average precipitation0.09 in
Chance of precipitation30%
Record high92° (2013)
Record low54° (1986)
Mon, 3178° / 65°0.06Climate normal
78 °Climate normal

Markham, Monday, 31 August

Climate normal for this date — 60-year average.

Average high78°
Average low65°
Average precipitation0.06 in
Chance of precipitation23%
Record high89° (2012)
Record low55° (2023)
Tue, 0178° / 65°0.13Climate normal
78 °Climate normal

Markham, Tuesday, 1 September

Climate normal for this date — 60-year average.

Average high78°
Average low65°
Average precipitation0.13 in
Chance of precipitation30%
Record high94° (2011)
Record low54° (1967)
Wed, 0279° / 65°0.06Climate normal
79 °Climate normal

Markham, Wednesday, 2 September

Climate normal for this date — 60-year average.

Average high79°
Average low65°
Average precipitation0.06 in
Chance of precipitation27%
Record high92° (2011)
Record low52° (1965)
Thu, 0379° / 65°0.07Climate normal
79 °Climate normal

Markham, Thursday, 3 September

Climate normal for this date — 60-year average.

Average high79°
Average low65°
Average precipitation0.07 in
Chance of precipitation23%
Record high93° (2023)
Record low53° (1974)
Fri, 0477° / 64°0.09Climate normal
77 °Climate normal

Markham, Friday, 4 September

Climate normal for this date — 60-year average.

Average high77°
Average low64°
Average precipitation0.09 in
Chance of precipitation33%
Record high91° (2023)
Record low50° (2025)
Sat, 0577° / 63°0.07Climate normal
77 °Climate normal

Markham, Saturday, 5 September

Climate normal for this date — 60-year average.

Average high77°
Average low63°
Average precipitation0.07 in
Chance of precipitation27%
Record high90° (2023)
Record low53° (2010)
Sun, 0677° / 64°0.1Climate normal
77 °Climate normal

Markham, Sunday, 6 September

Climate normal for this date — 60-year average.

Average high77°
Average low64°
Average precipitation0.1 in
Chance of precipitation37%
Record high91° (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 Markham, 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 Markham, 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.