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
ROCK-RAPIDS 31 1974-09-03 26 1894-09-10 10-07 10-24 11-04
CASCADE 32 1955-09-11 28 1953-09-22 10-07 10-28 11-12
MANCHESTER-2 29 2007-09-15 27 1984-09-16 10-07 10-28 11-10
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
ESTHERVILLE-2-N 30 2007-09-15 28 1991-09-20 10-07 10-28 11-05
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
BRITT 31 2007-09-15 25 1983-09-22 10-09 10-28 11-10
Spencer 31 1974-09-03 28 2007-09-15 10-09 10-27 11-04
Iowa - Northwest Climate Division 32 1974-09-03 28 1991-09-19 10-09 10-28 11-04
GRUNDY-CENTER 31 2007-09-15 27 1974-09-22 10-09 10-28 11-10
HAWARDEN 31 1974-09-03 24 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
CLARION 32 1974-09-03 25 1974-09-22 10-09 10-28 11-09
Iowa - Northeast Climate Division 32 2007-09-15 27 1974-09-22 10-10 11-03 11-11
NORTHWOOD 31 1953-09-13 26 1974-09-22 10-10 10-28 11-08
CHARLES-CITY 32 1955-09-12 28 1991-09-20 10-10 11-03 11-11
Emmetsburg 32 2011-09-15 24 1995-09-22 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
TOLEDO 31 2007-09-15 28 1962-09-20 10-10 10-29 11-12
TRIPOLI-4-N 31 2007-09-15 27 1974-09-22 10-10 11-02 11-12
HUMBOLDT-2 31 2011-09-15 26 1974-09-22 10-10 11-02 11-10
FOREST-CITY 30 2011-09-15 26 1974-09-22 10-10 10-28 11-10
PERRY 32 1955-09-12 28 1974-09-22 10-10 11-02 11-11
DECORAH-2-N 32 1915-08-30 28 1946-09-02 10-10 11-01 11-10
Eldora 32 1962-09-20 28 1974-09-22 10-10 11-03 11-10
IOWA-FALLS 32 1976-09-10 26 1974-09-22 10-10 10-29 11-10
CARROLL-2-SSW 28 1974-09-03 28 1974-09-03 10-10 10-28 11-10
INDEPENDENCE-2-W 32 1974-09-03 28 1975-09-13 10-10 10-29 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
MASON-CITY 30 1915-08-30 28 1923-09-14 10-10 10-28 11-09
FAYETTE 32 1949-09-01 27 1902-09-12 10-10 10-28 11-10
OELWEIN-2-S 28 1955-09-11 28 1955-09-11 10-10 11-02 11-10
Boone 32 1975-09-12 28 1981-09-18 10-10 11-02 11-11
SAC-CITY 32 1974-09-03 27 1974-09-22 10-10 11-02 11-11
ANAMOSA-1-WNW 29 1955-09-12 27 1956-09-20 10-10 10-29 11-12
HAMPTON-2-NW 32 1955-09-11 28 1955-09-12 10-12 11-02 11-10
WEBSTER-CITY 30 1955-09-11 25 1929-09-18 10-12 10-28 11-10
WATERLOO 32 1917-09-11 28 1929-09-18 10-13 11-02 11-11
LEMARS 31 1955-09-11 28 1902-09-12 10-13 10-28 11-08
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
HARLAN 29 1991-09-19 27 1951-09-28 10-16 11-02 11-11
FORT-DODGE 32 1974-09-03 28 1974-09-22 10-16 11-02 11-11
WAUKON 32 2011-09-16 27 1984-09-26 10-16 11-02 11-11
OAKLAND-2-E 32 1974-09-03 28 1995-09-22 10-16 11-03 11-11
PRIMGHAR 31 1984-09-15 27 1991-09-19 10-16 11-02 11-10
GRINNELL-3-SW 31 1976-09-10 27 1991-09-20 10-17 11-02 11-12
Iowa - West Central Climate Division 29 1991-09-19 28 1995-09-22 10-17 11-02 11-11
Iowa - Central Climate Division 32 1991-09-19 27 1984-09-29 10-17 11-03 11-19
MAQUOKETA-2-W 31 1917-09-11 28 1983-09-23 10-17 11-03 11-13
NEW-HAMPTON 28 1949-09-01 28 1949-09-01 10-17 11-01 11-10
GUTHRIE-CENTER 31 1893-09-02 28 1991-09-19 10-17 11-02 11-11
CORNING 32 1902-09-12 27 1983-09-21 10-17 11-02 11-20
WILLIAMSBURG 31 1955-09-12 28 1991-09-20 10-17 11-04 11-20
CHARITON 32 1955-09-12 28 1991-09-20 10-17 11-04 11-20
BELLE-PLAINE 32 1955-09-12 28 1991-09-20 10-17 11-03 11-20
STORM-LAKE-2-E 32 1902-09-12 28 1929-09-18 10-17 11-02 11-10
ROCKWELL-CITY 32 1902-09-12 28 1929-09-18 10-17 11-01 11-10
BELLEVUE-L-AND-D-12 31 1956-09-20 25 1995-09-23 10-17 11-04 11-21
ALGONA 29 1893-09-02 27 1929-09-18 10-17 11-02 11-10
ATLANTIC-1-NE 30 1893-09-02 28 1902-09-12 10-17 11-02 11-10
MARSHALLTOWN 31 1955-09-12 28 1896-09-20 10-17 11-02 11-11
Iowa - Southwest Climate Division 29 1991-09-19 28 1995-09-22 10-18 11-03 11-20
ANKENY-3-S 32 1991-09-20 28 1984-09-26 10-18 11-04 11-20
Creston 28 1991-09-19 28 1991-09-19 10-18 11-03 11-20
ALLISON 30 1991-09-20 28 1984-09-26 10-18 11-03 11-12
CASTANA-EXP-FARM 30 1991-09-19 28 1995-09-22 10-18 11-02 11-12
NEWTON 29 1974-09-22 27 1972-09-30 10-18 11-05 11-21
Holstein 31 1991-09-20 28 1984-09-29 10-18 11-05 11-21
Iowa - South Central Climate Division 31 1991-09-19 27 1984-09-29 10-18 11-05 11-21
Allerton 31 1991-09-19 27 1984-09-29 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
BEDFORD-1-NNW 27 1991-09-19 27 1991-09-19 10-18 11-04 11-21
SIGOURNEY 31 1995-09-22 28 1964-09-28 10-18 11-05 11-21
OSCEOLA-3-WSW 31 2007-09-15 28 1974-09-22 10-18 11-04 11-20
DENISON 29 1902-09-12 21 1918-09-21 10-18 11-02 11-11
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
LOGAN 30 1902-09-12 28 1902-09-13 10-18 11-02 11-11
WINTERSET 31 1955-09-12 28 1962-09-20 10-18 11-03 11-20
Iowa Average 31 1902-09-13 27 1926-09-26 10-18 11-03 11-19
VINTON 32 1953-09-13 28 1982-09-21 10-18 11-03 11-21
AMES-8-WSW 31 1902-09-13 26 1918-09-21 10-18 11-02 11-12
TIPTON 32 1902-09-13 28 1991-09-20 10-18 11-05 11-21
Lamoni 32 1991-09-19 24 1974-10-02 10-19 11-05 11-21
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
MOUNT-AYR 32 1902-09-13 28 1991-09-19 10-19 11-05 11-21
CLINTON-1 31 1902-09-13 28 1928-09-25 10-19 11-09 11-22
MOUNT-PLEASANT 29 1991-09-20 25 1974-10-02 10-19 11-10 11-24
CLARINDA 31 1902-09-13 28 1918-09-21 10-19 11-03 11-19
Donnellson 31 1991-09-20 27 1984-09-29 10-19 11-05 11-21
SHENANDOAH-1-NE 30 1980-09-17 26 1983-09-23 10-19 11-05 11-21
INDIANOLA-2-SSW 30 1979-09-15 28 1979-09-22 10-19 11-08 11-21
GREENFIELD 32 1981-09-17 28 1995-09-22 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
SIDNEY 30 1991-09-19 28 1995-09-22 10-19 11-08 11-23
KNOXVILLE 31 1991-09-19 27 1974-10-02 10-19 11-07 11-21
ALBIA 31 1991-09-19 25 1984-09-29 10-19 11-10 11-21
BLOOMFIELD 31 1991-09-20 25 1974-10-02 10-19 11-06 11-24
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
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
KEOSAUQUA 31 1917-09-11 28 1916-09-18 10-24 11-10 11-22
MUSCATINE 29 1991-09-20 26 1984-09-29 10-25 11-10 11-24
DUBUQUE-LOCK-AND-DAM 31 1956-09-20 24 1899-09-30 10-25 11-10 11-22
Wapello 31 1991-09-20 24 1942-09-28 10-25 11-10 11-22
Iowa - Southeast Climate Division 32 1991-09-20 26 1974-10-02 10-25 11-10 11-24
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