Iowa Environmental Mesonet

Iowa State University Department of Agronomy

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Freezing Dates

Using the NWS COOP data archive, significant dates relating to fall are extracted and presented on this page. The specific dates are the first occurance of that temperature and may have occured again in subsequent years.
The "Record Lows" columns show the first fall occurance of a low temperature. The "Average Lows" column shows when certain climatological thresholds are surpassed in the fall.

COOP Site: Record Lows: Average Lows:
Temp <= 32°F Temp <= 28°F Below 40°F Below 32°F Below 28°F
Temp: Date: Temp: Date:
ROCK-RAPIDS 31 1974-09-03 26 1894-09-10 10-06 10-24 11-03
CHEROKEE 31 1974-09-03 27 1955-09-11 10-07 10-26 11-04
SIBLEY-5-NNE 30 1974-09-03 23 1955-09-11 10-04 10-26 11-03
POCAHONTAS 30 2007-09-15 28 1983-09-20 10-07 10-28 11-05
CLARION 32 1974-09-03 25 1974-09-22 10-09 10-28 11-07
HAWARDEN 31 1974-09-03 24 1991-09-19 10-09 10-28 11-04
MANCHESTER-2 29 2007-09-15 27 1984-09-16 10-07 10-28 11-09
ESTHERVILLE-2-N 30 2007-09-15 28 1991-09-20 10-07 10-28 11-05
FAYETTE 32 1949-09-01 27 1902-09-12 10-10 10-28 11-10
Sheldon 32 1974-09-03 28 2007-09-15 10-09 10-28 11-04
GRUNDY-CENTER 31 2007-09-15 27 1974-09-22 10-07 10-29 11-07
CARROLL-2-SSW 28 1974-09-03 28 1974-09-03 10-07 10-29 11-08
CRESCO-1-NE 31 1975-09-13 27 1991-09-20 10-07 10-29 11-05
LEMARS 25 1893-09-02 25 1893-09-02 10-17 10-29 11-08
SIOUX-RAPIDS 31 1974-09-03 28 1991-09-19 10-09 10-29 11-06
Boone 32 1975-09-12 28 1981-09-18 10-10 11-01 11-04
MASON-CITY 30 1915-08-30 28 1923-09-14 10-10 11-01 11-08
MARSHALLTOWN 31 1955-09-12 28 1896-09-20 10-17 11-02 11-11
STORM-LAKE-2-E 32 1902-09-12 28 1929-09-18 10-17 11-02 11-08
LOGAN 30 1902-09-12 28 1902-09-13 10-18 11-02 11-12
ROCKWELL-CITY 32 1902-09-12 28 1929-09-18 10-17 11-02 11-10
AUDUBON 30 1955-09-12 28 1991-09-20 10-10 11-02 11-10
AMES-8-WSW 31 1902-09-13 26 1918-09-21 10-18 11-02 11-12
DENISON 29 1902-09-12 21 1918-09-21 10-18 11-02 11-12
HUMBOLDT-2 32 1976-09-17 26 1974-09-22 10-09 11-02 11-07
EMMETSBURG 31 1991-09-19 24 1995-09-22 10-10 11-02 11-08
PRIMGHAR 31 1984-09-15 27 1991-09-19 10-09 11-02 11-08
BRITT 31 2007-09-15 25 1983-09-22 10-09 11-02 11-08
FOREST-CITY 31 2007-09-15 26 1974-09-22 10-09 11-02 11-08
SIOUX-CITY-WSO-AP 32 2007-09-15 25 1995-09-22 10-15 11-02 11-08
WAUKON 32 1956-09-20 27 1984-09-26 10-10 11-02 11-09
NORTHWOOD 31 1953-09-13 26 1974-09-22 10-09 11-02 11-05
GUTHRIE-CENTER 31 1893-09-02 28 1991-09-19 10-17 11-02 11-11
ALGONA 29 1893-09-02 27 1929-09-18 10-17 11-02 11-10
NEW-HAMPTON 28 1949-09-01 28 1949-09-01 10-17 11-02 11-10
ATLANTIC-1-NE 30 1893-09-02 28 1902-09-12 10-17 11-02 11-10
FORT-DODGE 32 1974-09-03 28 1995-09-22 10-09 11-02 11-10
IOWA-FALLS 32 1976-09-10 26 1974-09-22 10-10 11-02 11-07
SAC-CITY 32 1974-09-03 27 1974-09-22 10-10 11-02 11-11
WATERLOO 32 1917-09-11 28 1929-09-18 10-13 11-02 11-10
WEBSTER-CITY 30 1955-09-11 25 1929-09-18 10-13 11-02 11-10
HAMPTON-2-NW 32 1955-09-11 28 1955-09-12 10-17 11-02 11-10
OELWEIN-2-S 28 1955-09-11 28 1955-09-11 10-10 11-02 11-10
DECORAH-2-N 32 1915-08-30 28 1946-09-02 10-10 11-02 11-10
ONAWA 30 1955-09-11 28 1991-09-19 10-19 11-02 11-11
Eldora 32 1962-09-20 28 1974-09-22 10-10 11-03 11-10
TOLEDO 31 2007-09-15 28 1962-09-20 10-10 11-03 11-10
CLARINDA 31 1902-09-13 28 1918-09-21 10-19 11-03 11-19
GRINNELL-3-SW 31 1976-09-10 27 1991-09-20 10-17 11-03 11-12
OSAGE 32 2007-09-15 28 1974-09-22 10-17 11-03 11-10
TRIPOLI-4-N 31 2007-09-15 27 1974-09-22 10-10 11-03 11-10
ALLISON 30 1991-09-20 28 1984-09-26 10-18 11-03 11-16
HARLAN 29 1991-09-19 27 1951-09-28 10-17 11-03 11-10
Creston 28 1991-09-19 28 1991-09-19 10-18 11-03 11-20
INDEPENDENCE-2-W 32 1974-09-03 28 1975-09-13 10-10 11-03 11-10
CASTANA-EXP-FARM 30 1991-09-19 28 1995-09-22 10-18 11-03 11-19
OAKLAND-2-E 32 1974-09-03 28 1995-09-22 10-10 11-03 11-10
Iowa Average 31 1902-09-13 27 1926-09-26 10-19 11-03 11-19
PERRY 32 1955-09-12 28 1974-09-22 10-09 11-03 11-10
CHARLES-CITY 32 1955-09-12 28 1991-09-20 10-10 11-03 11-10
ANAMOSA-1-WNW 29 1955-09-12 27 1956-09-20 10-10 11-03 11-12
CASCADE 32 1955-09-11 28 1953-09-22 10-07 11-03 11-10
VINTON 32 1953-09-13 28 1982-09-21 10-10 11-03 11-20
CORNING 32 1902-09-12 27 1983-09-21 10-18 11-03 11-19
GREENFIELD 32 1981-09-17 28 1995-09-22 10-19 11-04 11-20
CHARITON 32 1955-09-12 28 1991-09-20 10-18 11-04 11-20
ANKENY-3-S 32 1991-09-20 28 1984-09-26 10-18 11-04 11-20
BELLEVUE-L-AND-D-12 31 1991-09-20 25 1995-09-23 10-18 11-04 11-21
GLENWOOD 27 1901-09-18 27 1901-09-18 10-19 11-04 11-21
BELLE-PLAINE 32 1955-09-12 28 1991-09-20 10-18 11-04 11-19
WILLIAMSBURG 31 1955-09-12 28 1991-09-20 10-18 11-04 11-20
WINTERSET 31 1955-09-12 28 1962-09-20 10-18 11-04 11-10
JEFFERSON 32 2007-09-16 23 1974-10-02 10-18 11-04 11-19
BEDFORD-1-NNW 27 1991-09-19 27 1991-09-19 10-19 11-04 11-20
MAQUOKETA-2-W 31 1917-09-11 28 1983-09-23 10-17 11-04 11-13
RED-OAK 32 1993-09-15 28 1995-09-22 10-18 11-04 11-20
OSCEOLA-3-WSW 31 2007-09-15 28 1974-09-22 10-18 11-04 11-20
SIDNEY 30 1991-09-19 28 1995-09-22 10-27 11-05 11-24
TIPTON 32 1902-09-13 28 1991-09-20 10-19 11-05 11-21
BLOOMFIELD 31 1991-09-20 25 1974-10-02 10-19 11-05 11-21
Lamoni 32 1991-09-19 24 1974-10-02 10-19 11-05 11-21
SIGOURNEY 31 1995-09-22 28 1964-09-28 10-19 11-05 11-21
MOUNT-AYR 32 1902-09-13 28 1991-09-19 10-23 11-05 11-21
OSKALOOSA 31 1902-09-13 27 1991-09-20 10-19 11-05 11-21
CENTERVILLE 32 1991-09-19 27 1979-10-05 10-19 11-05 11-23
GUTTENBERG-L-AND-D-10 32 1973-09-18 28 1984-09-29 10-19 11-05 11-21
SHENANDOAH-1-NE 30 1980-09-17 26 1983-09-23 10-19 11-05 11-20
NEWTON 29 1974-09-22 27 1972-09-30 10-18 11-05 11-21
CEDAR-RAPIDS-1 32 2007-09-15 24 1926-09-26 10-19 11-05 11-21
Des Moines Airport 31 1995-09-22 28 1984-09-29 10-19 11-05 11-20
CLINTON-1 22 1924-08-31 22 1924-08-31 10-19 11-06 11-22
IOWA-CITY 32 1956-09-20 24 1958-10-01 10-19 11-06 11-21
ALBIA 31 1991-09-19 25 1984-09-29 10-25 11-06 11-21
KNOXVILLE 31 1991-09-19 27 1974-10-02 10-19 11-07 11-21
WASHINGTON 30 1902-09-13 28 1983-09-23 10-24 11-08 11-22
INDIANOLA-2-SSW 30 1979-09-15 28 1979-09-22 10-19 11-08 11-21
FAIRFIELD 32 1917-09-11 28 1918-09-21 10-24 11-08 11-22
Ottumwa 29 1981-08-03 27 1984-09-29 10-24 11-08 11-24
KEOSAUQUA 31 1917-09-11 28 1916-09-18 10-24 11-09 11-22
FORT-MADISON 32 1983-09-23 27 1974-10-02 10-28 11-10 11-24
DUBUQUE-LOCK-AND-DAM 31 1956-09-20 24 1899-09-30 10-25 11-10 11-22
MOUNT-PLEASANT 29 1991-09-20 25 1974-10-02 10-19 11-10 11-21
Burlington 32 1991-09-20 26 2003-10-02 10-27 11-10 11-24
MUSCATINE 29 1991-09-20 26 1984-09-29 10-19 11-10 11-24
Le Claire L&D 14 32 1984-09-29 25 1974-10-02 10-28 11-11 11-24