Cook County climate

Cook County Weather in September

NOAA 1991-2020 normals for Grand Marais, 17.5 km from Cook County

Average highs run from 66°F on September 1 to 57°F on September 30, and lows from 52°F to 42°F. Normal precipitation for the month is 2.83 in over about 10 wet days.

September day by day

The normal high and low for each date, and the record, in °F.

Normal daily high and low temperature at Cook County, in °F, with the record for each date.20406080100151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

September at a glance

Average high
62°F
Average low
47°F
Precipitation
2.83 in
Record high
88°FSep 11, 2011
Record low
28°FSep 27, 2000
Chance of a freeze
33%
Daylight
13 h 22 min to 11 h 43 min
Cloud cover
63%
Humidity
76%
Dew point
47°F
Wind
7.4 mph

Every day of the month

A wet day has at least 0.01 inch of precipitation; snow means at least 0.1 inch of snowfall.

DateNormal highNormal lowRecord highRecord lowChance wetChance of snow
Sep 166°F52°F79°F 201345°F 201931%0%
Sep 266°F51°F85°F 200748°F 201032%0%
Sep 366°F51°F78°F 200143°F 202032%0%
Sep 466°F51°F76°F 201241°F 202532%0%
Sep 565°F51°F84°F 199839°F 201032%0%
Sep 665°F50°F79°F 199841°F 202532%0%
Sep 765°F50°F78°F 201541°F 202032%0%
Sep 865°F50°F79°F 202436°F 202032%0%
Sep 964°F50°F79°F 200240°F 202033%0%
Sep 1064°F49°F75°F 200536°F 202033%0%
Sep 1164°F49°F88°F 201139°F 201433%0%
Sep 1263°F49°F72°F 200236°F 200733%0%
Sep 1363°F48°F73°F 200041°F 200133%0%
Sep 1463°F48°F75°F 201833°F 200733%0%
Sep 1562°F48°F76°F 200932°F 200733%0%
Sep 1662°F47°F75°F 202433°F 201133%0%
Sep 1762°F47°F76°F 202533°F 202033%0%
Sep 1861°F47°F76°F 202434°F 202033%0%
Sep 1961°F46°F75°F 202437°F 200633%0%
Sep 2061°F46°F73°F 200533°F 200633%0%
Sep 2160°F46°F71°F 202432°F 199933%0%
Sep 2260°F45°F73°F 201737°F 200233%0%
Sep 2359°F45°F76°F 201732°F 200033%0%
Sep 2459°F45°F69°F 201232°F 200033%0%
Sep 2559°F44°F77°F 202535°F 201033%0%
Sep 2658°F44°F71°F 200834°F 201033%0%
Sep 2758°F44°F74°F 202528°F 200033%0%
Sep 2858°F43°F74°F 202432°F 200333%0%
Sep 2957°F43°F70°F 202431°F 200332%0%
Sep 3057°F42°F70°F 202433°F 200332%0%

Chance of rain

The chance of at least 0.01 inch of precipitation on each date at Cook County, in percent, and of at least 0.1 inch of snowfall.0102030401102030
  • Chance of a wet day
  • Chance of snowfall

Sunrise and sunset

Times for 2026, local time (CDT).

September 1
sunrise 6:21 AM, sunset 7:43 PM
September 30
sunrise 7:00 AM, sunset 6:43 PM

Every day of September: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00213282 (Grand Marais), public domain. Records: NOAA GHCN-Daily, station USW00094992, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.