As of 01:55 CDT

Weather in Merrimac, IL

75°

Merrimac, Sunday, 9 August, 01:55

Mostly clear. Feels like 76°. High 96°, low 72°.

Pressure30.00 inHg

Wind5.6 mph S

Humidity91%

Visibility6.2 mi

Dew point72°

See detailed hourly forecast

Monthly outlook for Merrimac, IL: average high 101.3°, average low 74.8°. That is 8.6° above the climate normal for August. Precipitation is expected on 4 days (about 0.4 inches), against a normal of 5 days and 1.7 inches. The warmest day looks like 20 August (115.4°), the coolest 15 August (66.7°).

101.3°/74.8°

Average high / low

+8.6°

Above normal

4 / 5

Wet days / normal

0.4 in

Precipitation this month

Ten-day blocks vs climate normal

Period	Forecast high	Normal	Difference
9 August – 18 August	95.5°	85.8°	+5.4°
19 August – 28 August	111°	86°	+13.9°
29 August – 7 September	at normal	83.6°	—

August records over 66 years

103.1°15 August 2007All-time high

49.6°29 August 1986All-time low

Climate normals and records are computed from the nearest reference point — Lakeshire (12 mi).

Mon, 10101° / 72°

101 °

Merrimac, Monday, 10 August

Light rain. High 101°, low 72°.

Pressure29.94 inHg

Wind11.9 mph SW

Humidity38%

Visibility6.2 mi

Dew point67°

Tue, 11103° / 73°

103 °

Merrimac, Tuesday, 11 August

Partly cloudy. High 103°, low 73°.

Pressure29.88 inHg

Wind12.2 mph SW

Humidity32%

Visibility6.2 mi

Dew point65°

Wed, 12102° / 79°

0.02

102 °

Merrimac, Wednesday, 12 August

Light rain. High 102°, low 79°.

Pressure29.83 inHg

Wind9.5 mph W

Humidity41%

Visibility6.2 mi

Dew point68°

Thu, 1394° / 74°

0.09

94 °

Merrimac, Thursday, 13 August

Light rain. High 94°, low 74°.

Pressure29.88 inHg

Wind15.3 mph E

Humidity56%

Visibility—

Dew point71°

Fri, 1476° / 67°

0.04

76 °

Merrimac, Friday, 14 August

Light rain. High 76°, low 67°.

Pressure30.03 inHg

Wind12.4 mph E

Humidity78%

Visibility—

Dew point67°

Sat, 1596° / 67°

0.07

96 °

Merrimac, Saturday, 15 August

Light rain. High 96°, low 67°.

Pressure30.09 inHg

Wind13.3 mph E

Humidity55%

Visibility—

Dew point66°

Sun, 1696° / 72°

96 °

Merrimac, Sunday, 16 August

Partly cloudy. High 96°, low 72°.

Pressure30.03 inHg

Wind9.9 mph NW

Humidity53%

Visibility—

Dew point69°

Mon, 1792° / 73°

0.11

92 °

Merrimac, Monday, 17 August

Light rain. High 92°, low 73°.

Pressure30.03 inHg

Wind10.5 mph E

Humidity58%

Visibility—

Dew point69°

Tue, 1898° / 69°

0.03

98 °

Merrimac, Tuesday, 18 August

Light rain. High 98°, low 69°.

Pressure29.94 inHg

Wind13.8 mph E

Humidity49%

Visibility—

Dew point68°

Wed, 19112° / 78°

0.01

112 °

Merrimac, Wednesday, 19 August

Light rain. High 112°, low 78°.

Pressure29.85 inHg

Wind15.3 mph S

Humidity22%

Visibility—

Dew point57°

Thu, 20115° / 82°

115 °

Merrimac, Thursday, 20 August

Clear. High 115°, low 82°.

Pressure29.83 inHg

Wind13.3 mph W

Humidity16%

Visibility—

Dew point52°

Fri, 21112° / 81°

112 °

Merrimac, Friday, 21 August

Clear. High 112°, low 81°.

Pressure29.83 inHg

Wind12.3 mph W

Humidity19%

Visibility—

Dew point54°

Sat, 22114° / 79°

114 °

Merrimac, Saturday, 22 August

Light rain. High 114°, low 79°.

Pressure29.85 inHg

Wind9.8 mph S

Humidity25%

Visibility—

Dew point58°

Sun, 23110° / 79°

0.06

110 °

Merrimac, Sunday, 23 August

Light rain. High 110°, low 79°.

Pressure29.85 inHg

Wind7.8 mph S

Humidity25%

Visibility—

Dew point60°

Mon, 24103° / 79°

0.01

103 °

Merrimac, Monday, 24 August

Light rain. High 103°, low 79°.

Pressure29.94 inHg

Wind9.6 mph E

Humidity31%

Visibility—

Dew point63°

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

Tue, 2587° / 69°

0.07

87 °

Merrimac, Tuesday, 25 August

Climate normal for this date — 60-year average.

Average high87°

Average low69°

Average precipitation0.07 in

Chance of precipitation23%

Record high100° (2023)

Record low57° (2015)

Wed, 2687° / 69°

0.12

87 °

Merrimac, Wednesday, 26 August

Climate normal for this date — 60-year average.

Average high87°

Average low69°

Average precipitation0.12 in

Chance of precipitation30%

Record high98° (1983)

Record low56° (2015)

Thu, 2786° / 69°

0.1

86 °

Merrimac, Thursday, 27 August

Climate normal for this date — 60-year average.

Average high86°

Average low69°

Average precipitation0.1 in

Chance of precipitation30%

Record high98° (1983)

Record low56° (2015)

Fri, 2886° / 69°

0.09

86 °

Merrimac, Friday, 28 August

Climate normal for this date — 60-year average.

Average high86°

Average low69°

Average precipitation0.09 in

Chance of precipitation27%

Record high97° (1990)

Record low54° (1967)

Sat, 2985° / 68°

0.07

85 °

Merrimac, Saturday, 29 August

Climate normal for this date — 60-year average.

Average high85°

Average low68°

Average precipitation0.07 in

Chance of precipitation25%

Record high97° (1984)

Record low50° (1986)

Sun, 3084° / 68°

0.13

84 °

Merrimac, Sunday, 30 August

Climate normal for this date — 60-year average.

Average high84°

Average low68°

Average precipitation0.13 in

Chance of precipitation30%

Record high97° (2013)

Record low53° (1986)

Mon, 3184° / 68°

0.11

84 °

Merrimac, Monday, 31 August

Climate normal for this date — 60-year average.

Average high84°

Average low68°

Average precipitation0.11 in

Chance of precipitation32%

Record high101° (2013)

Record low56° (1967)

Tue, 0184° / 68°

0.1

84 °

Merrimac, Tuesday, 1 September

Climate normal for this date — 60-year average.

Average high84°

Average low68°

Average precipitation0.1 in

Chance of precipitation30%

Record high98° (2011)

Record low53° (1967)

Wed, 0283° / 67°

0.11

83 °

Merrimac, Wednesday, 2 September

Climate normal for this date — 60-year average.

Average high83°

Average low67°

Average precipitation0.11 in

Chance of precipitation35%

Record high97° (2011)

Record low53° (1974)

Thu, 0383° / 67°

0.11

83 °

Merrimac, Thursday, 3 September

Climate normal for this date — 60-year average.

Average high83°

Average low67°

Average precipitation0.11 in

Chance of precipitation25%

Record high96° (2011)

Record low51° (1974)

Fri, 0483° / 66°

0.13

83 °

Merrimac, Friday, 4 September

Climate normal for this date — 60-year average.

Average high83°

Average low66°

Average precipitation0.13 in

Chance of precipitation27%

Record high97° (1960)

Record low52° (1974)

Sat, 0583° / 65°

0.05

83 °

Merrimac, Saturday, 5 September

Climate normal for this date — 60-year average.

Average high83°

Average low65°

Average precipitation0.05 in

Chance of precipitation20%

Record high96° (1998)

Record low51° (1974)

Sun, 0683° / 65°

0.04

83 °

Merrimac, Sunday, 6 September

Climate normal for this date — 60-year average.

Average high83°

Average low65°

Average precipitation0.04 in

Chance of precipitation17%

Record high98° (1990)

Record low52° (1988)

Mon, 0783° / 65°

0.07

83 °

Merrimac, Monday, 7 September

Climate normal for this date — 60-year average.

Average high83°

Average low65°

Average precipitation0.07 in

Chance of precipitation20%

Record high96° (1960)

Record low48° (1988)

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 Merrimac, 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 Merrimac, 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.