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:
Elkader 6SSW (Osborn) 28 2007-09-15 28 2007-09-15 09-27 10-16 10-28
CRESCO-1-NE 31 1975-09-13 27 1991-09-20 10-05 10-28 11-05
CASCADE 32 1955-09-11 28 1953-09-22 10-07 10-28 11-12
SIBLEY-5-NNE 30 1974-09-03 23 1955-09-11 10-07 10-26 11-03
POCAHONTAS 30 2007-09-15 28 1983-09-20 10-07 10-28 11-07
MANCHESTER-2 29 2007-09-15 27 1984-09-16 10-07 10-28 11-10
ESTHERVILLE-2-N 30 2007-09-15 28 1991-09-20 10-07 10-28 11-05
ROCK-RAPIDS 31 1974-09-03 26 1894-09-10 10-07 10-24 11-04
Sheldon 32 1974-09-03 28 2007-09-15 10-07 10-26 11-04
CHEROKEE 31 1974-09-03 27 1955-09-11 10-07 10-26 11-04
BRITT 31 2007-09-15 25 1983-09-22 10-09 10-28 11-10
GRUNDY-CENTER 31 2007-09-15 27 1974-09-22 10-09 10-28 11-10
CLARION 32 1974-09-03 25 1974-09-22 10-09 10-28 11-09
HAWARDEN 31 1974-09-03 24 1991-09-19 10-09 10-28 11-04
Iowa - Northwest Climate Division 32 1974-09-03 28 1991-09-19 10-09 10-28 11-04
SIOUX-RAPIDS 31 1974-09-03 28 1991-09-19 10-09 10-28 11-07
Spencer 31 1974-09-03 28 2007-09-15 10-09 10-27 11-04
IOWA-FALLS 32 1976-09-10 26 1974-09-22 10-10 10-29 11-10
FAYETTE 32 1949-09-01 27 1902-09-12 10-10 10-28 11-10
CHARLES-CITY 32 1955-09-12 28 1991-09-20 10-10 11-03 11-11
CARROLL-2-SSW 28 1974-09-03 28 1974-09-03 10-10 10-28 11-10
HUMBOLDT-2 31 2011-09-15 26 1974-09-22 10-10 11-02 11-10
DECORAH-2-N 32 1915-08-30 28 1946-09-02 10-10 11-01 11-10
NORTHWOOD 31 1953-09-13 26 1974-09-22 10-10 10-28 11-08
TRIPOLI-4-N 31 2007-09-15 27 1974-09-22 10-10 11-02 11-12
Eldora 32 1962-09-20 28 1974-09-22 10-10 11-03 11-10
SAC-CITY 32 1974-09-03 27 1974-09-22 10-10 11-02 11-11
PERRY 32 1955-09-12 28 1974-09-22 10-10 11-02 11-11
MASON-CITY 30 1915-08-30 28 1923-09-14 10-10 10-28 11-09
TOLEDO 31 2007-09-15 28 1962-09-20 10-10 10-29 11-12
Emmetsburg 32 2011-09-15 24 1995-09-22 10-10 11-02 11-10
Iowa - Northeast Climate Division 32 2007-09-15 27 1974-09-22 10-10 11-03 11-11
INDEPENDENCE-2-W 32 1974-09-03 28 1975-09-13 10-10 10-29 11-10
OELWEIN-2-S 28 1955-09-11 28 1955-09-11 10-10 11-02 11-10
Milford 32 1974-09-03 27 1983-09-21 10-10 10-31 11-04
AUDUBON 30 1955-09-12 28 1962-09-20 10-10 11-02 11-10
Iowa - North Central Climate Division 30 2011-09-15 26 1974-09-22 10-10 11-02 11-10
ANAMOSA-1-WNW 29 1955-09-12 27 1956-09-20 10-10 10-29 11-12
FOREST-CITY 30 2011-09-15 26 1974-09-22 10-10 10-28 11-10
Boone 32 1975-09-12 28 1981-09-18 10-10 11-02 11-11
WEBSTER-CITY 30 1955-09-11 25 1929-09-18 10-12 10-28 11-10
HAMPTON-2-NW 32 1955-09-11 28 1955-09-12 10-12 11-02 11-10
LEMARS 31 1955-09-11 28 1902-09-12 10-13 10-28 11-08
WATERLOO 32 1917-09-11 28 1929-09-18 10-13 11-02 11-11
SIOUX-CITY-WSO-AP 32 2007-09-15 25 1995-09-22 10-15 11-02 11-10
OSAGE 32 2007-09-15 28 1974-09-22 10-15 11-02 11-11
PRIMGHAR 31 1984-09-15 27 1991-09-19 10-16 11-02 11-10
OAKLAND-2-E 32 1974-09-03 28 1995-09-22 10-16 11-03 11-11
HARLAN 29 1991-09-19 27 1951-09-28 10-16 11-02 11-11
WAUKON 32 2011-09-16 27 1984-09-26 10-16 11-02 11-11
FORT-DODGE 32 1974-09-03 28 1974-09-22 10-16 11-02 11-11
GRINNELL-3-SW 31 1976-09-10 27 1991-09-20 10-17 11-02 11-12
MAQUOKETA-2-W 31 1917-09-11 28 1983-09-23 10-17 11-03 11-13
CHARITON 32 1955-09-12 28 1991-09-20 10-17 11-04 11-20
ATLANTIC-1-NE 30 1893-09-02 28 1902-09-12 10-17 11-02 11-10
NEW-HAMPTON 28 1949-09-01 28 1949-09-01 10-17 11-01 11-10
Iowa - Central Climate Division 32 1991-09-19 27 1984-09-29 10-17 11-03 11-19
Iowa - West Central Climate Division 29 1991-09-19 28 1995-09-22 10-17 11-02 11-11
GUTHRIE-CENTER 31 1893-09-02 28 1991-09-19 10-17 11-02 11-11
WILLIAMSBURG 31 1955-09-12 28 1991-09-20 10-17 11-04 11-20
ALGONA 29 1893-09-02 27 1929-09-18 10-17 11-02 11-10
BELLE-PLAINE 32 1955-09-12 28 1991-09-20 10-17 11-03 11-20
BELLEVUE-L-AND-D-12 31 1956-09-20 25 1995-09-23 10-17 11-04 11-21
STORM-LAKE-2-E 32 1902-09-12 28 1929-09-18 10-17 11-02 11-10
MARSHALLTOWN 31 1955-09-12 28 1896-09-20 10-17 11-02 11-11
CORNING 32 1902-09-12 27 1983-09-21 10-17 11-02 11-20
ROCKWELL-CITY 32 1902-09-12 28 1929-09-18 10-17 11-01 11-10
Allerton 31 1991-09-19 27 1984-09-29 10-18 11-05 11-21
ALLISON 30 1991-09-20 28 1984-09-26 10-18 11-03 11-12
Creston 28 1991-09-19 28 1991-09-19 10-18 11-03 11-20
ANKENY-3-S 32 1991-09-20 28 1984-09-26 10-18 11-04 11-20
Holstein 31 1991-09-20 28 1984-09-29 10-18 11-05 11-21
CASTANA-EXP-FARM 30 1991-09-19 28 1995-09-22 10-18 11-02 11-12
Iowa - Southwest Climate Division 29 1991-09-19 28 1995-09-22 10-18 11-03 11-20
NEWTON 29 1974-09-22 27 1972-09-30 10-18 11-05 11-21
Iowa - East Central Climate Division 30 1991-09-20 28 1984-09-29 10-18 11-05 11-21
SIGOURNEY 31 1995-09-22 28 1964-09-28 10-18 11-05 11-21
BEDFORD-1-NNW 27 1991-09-19 27 1991-09-19 10-18 11-04 11-21
RED-OAK 32 1979-09-15 28 1995-09-22 10-18 11-03 11-20
JEFFERSON 32 2011-09-15 23 1974-10-02 10-18 11-03 11-12
WINTERSET 31 1955-09-12 28 1962-09-20 10-18 11-03 11-20
VINTON 32 1953-09-13 28 1982-09-21 10-18 11-03 11-21
TIPTON 32 1902-09-13 28 1991-09-20 10-18 11-05 11-21
Iowa Average 31 1902-09-13 27 1926-09-26 10-18 11-03 11-19
OSCEOLA-3-WSW 31 2007-09-15 28 1974-09-22 10-18 11-04 11-20
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 11-11
Iowa - South Central Climate Division 31 1991-09-19 27 1984-09-29 10-18 11-05 11-21
LOGAN 30 1902-09-12 28 1902-09-13 10-18 11-02 11-11
MOUNT-AYR 32 1902-09-13 28 1991-09-19 10-19 11-05 11-21
BLOOMFIELD 31 1991-09-20 25 1974-10-02 10-19 11-06 11-24
OSKALOOSA 31 1902-09-13 27 1991-09-20 10-19 11-05 11-21
ONAWA 30 1955-09-11 28 1991-09-19 10-19 11-02 11-11
GLENWOOD 30 1902-09-12 28 1902-09-13 10-19 11-03 11-21
Donnellson 31 1991-09-20 27 1984-09-29 10-19 11-05 11-21
CLINTON-1 31 1902-09-13 28 1928-09-25 10-19 11-09 11-22
CLARINDA 31 1902-09-13 28 1918-09-21 10-19 11-03 11-19
GREENFIELD 32 1981-09-17 28 1995-09-22 10-19 11-05 11-21
ALBIA 31 1991-09-19 25 1984-09-29 10-19 11-10 11-21
SIDNEY 30 1991-09-19 28 1995-09-22 10-19 11-08 11-23
SHENANDOAH-1-NE 30 1980-09-17 26 1983-09-23 10-19 11-05 11-21
GUTTENBERG-L-AND-D-10 32 1973-09-18 28 1984-09-29 10-19 11-06 11-21
KNOXVILLE 31 1991-09-19 27 1974-10-02 10-19 11-07 11-21
MOUNT-PLEASANT 29 1991-09-20 25 1974-10-02 10-19 11-10 11-24
Lamoni 32 1991-09-19 24 1974-10-02 10-19 11-05 11-21
INDIANOLA-2-SSW 30 1979-09-15 28 1979-09-22 10-19 11-08 11-21
CEDAR-RAPIDS-1 32 2007-09-15 24 1926-09-26 10-20 11-05 11-21
IOWA-CITY 32 1923-09-14 28 1916-09-18 10-20 11-06 11-22
KEOSAUQUA 31 1917-09-11 28 1916-09-18 10-24 11-10 11-22
Des Moines Airport 31 1995-09-22 26 1942-09-28 10-24 11-08 11-21
Ottumwa 32 2007-09-15 27 1984-09-29 10-24 11-10 11-23
WASHINGTON 30 1902-09-13 28 1983-09-23 10-24 11-08 11-22
FAIRFIELD 32 1917-09-11 28 1918-09-21 10-24 11-10 11-22
Wapello 31 1991-09-20 24 1942-09-28 10-25 11-10 11-22
MUSCATINE 29 1991-09-20 26 1984-09-29 10-25 11-10 11-24
Iowa - Southeast Climate Division 32 1991-09-20 26 1974-10-02 10-25 11-10 11-24
DUBUQUE-LOCK-AND-DAM 31 1956-09-20 24 1899-09-30 10-25 11-10 11-22
CENTERVILLE 32 1991-09-19 27 1979-10-05 10-26 11-10 11-23
Burlington 32 1991-09-20 26 2003-10-02 10-27 11-10 11-24
Le Claire L&D 14 32 1984-09-29 25 1974-10-02 10-28 11-11 11-24
Fort Madison 32 1983-09-23 27 1974-10-02 10-28 11-19 11-24