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:
CRESCO-1-NE 31 1975-09-13 27 1991-09-20 10-05 10-28 11-07
SIBLEY-5-NNE 30 1974-09-03 23 1955-09-11 10-07 10-26 11-03
ESTHERVILLE-2-N 32 2014-09-13 28 1991-09-20 10-07 10-28 11-07
Sheldon 32 1974-09-03 28 2007-09-15 10-07 10-27 11-04
CASCADE 32 1955-09-11 28 1953-09-22 10-07 11-03 11-12
ROCK-RAPIDS 31 1974-09-03 26 1894-09-10 10-07 10-24 11-05
CHEROKEE 31 1974-09-03 27 1955-09-11 10-07 10-26 11-04
MANCHESTER-2 32 2014-09-13 27 1984-09-16 10-07 10-28 11-10
CLARION 32 1974-09-03 25 1974-09-22 10-09 10-28 11-09
Spencer 31 1974-09-03 28 2007-09-15 10-09 10-27 11-03
BRITT 31 2007-09-15 25 1983-09-22 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
Elkader 6SSW (Osborn) 32 1893-08-29 0 2002-09-02 10-09 10-28 11-10
TOLEDO 31 2007-09-15 28 1962-09-20 10-10 11-03 11-12
FOREST-CITY 30 2011-09-15 26 1974-09-22 10-10 10-28 11-10
TRIPOLI-4-N 31 2007-09-15 27 1974-09-22 10-10 11-02 11-12
Emmetsburg 32 2011-09-15 24 1995-09-22 10-10 11-01 11-10
OSAGE 32 2007-09-15 28 1974-09-22 10-10 11-02 11-11
ANAMOSA-1-WNW 29 1955-09-12 27 1956-09-20 10-10 11-03 11-12
PERRY 32 1955-09-12 28 1974-09-22 10-10 11-02 11-11
Boone 32 1975-09-12 28 1981-09-18 10-10 11-03 11-11
POCAHONTAS 32 2014-09-13 28 1983-09-20 10-10 10-28 11-07
CHARLES-CITY 32 1955-09-12 28 1991-09-20 10-10 11-03 11-12
OELWEIN-2-S 28 1955-09-11 28 1955-09-11 10-10 11-02 11-10
NORTHWOOD 31 1953-09-13 26 1974-09-22 10-10 10-28 11-08
AUDUBON 30 1955-09-12 28 1962-09-20 10-10 11-01 11-10
GRUNDY-CENTER 31 2007-09-15 27 1974-09-22 10-10 10-29 11-10
Milford 32 1974-09-03 27 1983-09-21 10-10 10-31 11-07
SAC-CITY 32 1974-09-03 27 1974-09-22 10-10 11-01 11-11
INDEPENDENCE-2-W 32 1974-09-03 28 1975-09-13 10-10 10-29 11-10
Eldora 32 1962-09-20 28 1974-09-22 10-10 11-03 11-10
FAYETTE 32 1949-09-01 27 1902-09-12 10-10 10-28 11-10
MASON-CITY 30 1915-08-30 28 1923-09-14 10-10 11-01 11-09
DECORAH-2-N 32 1915-08-30 28 1946-09-02 10-10 11-01 11-10
FORT-DODGE 32 1974-09-03 28 1974-09-22 10-10 11-02 11-11
Iowa - Northwest Climate Division 32 1974-09-03 27 1902-09-13 10-10 10-28 11-08
CARROLL-2-SSW 28 1974-09-03 28 1974-09-03 10-10 10-28 11-10
IOWA-FALLS 32 1976-09-10 26 1974-09-22 10-10 11-02 11-10
HUMBOLDT-2 31 2011-09-15 26 1974-09-22 10-10 11-02 11-10
WEBSTER-CITY 30 1955-09-11 25 1929-09-18 10-13 11-01 11-10
WATERLOO 32 1917-09-11 28 1929-09-18 10-13 11-02 11-11
STORM-LAKE-2-E 32 1902-09-12 28 1929-09-18 10-13 11-02 11-10
LEMARS 31 1955-09-11 28 1902-09-12 10-13 10-29 11-08
OAKLAND-2-E 32 1974-09-03 28 1995-09-22 10-16 11-03 11-12
HARLAN 29 1991-09-19 27 1951-09-28 10-16 11-03 11-11
PRIMGHAR 31 1984-09-15 27 1991-09-19 10-16 11-02 11-10
WAUKON 32 2011-09-16 27 1984-09-26 10-16 11-02 11-10
Iowa - North Central Climate Division 30 2011-09-15 26 1974-09-22 10-17 11-02 11-10
BELLE-PLAINE 32 1955-09-12 28 1991-09-20 10-17 11-03 11-19
SIOUX-CITY-WSO-AP 30 1902-09-13 25 1995-09-22 10-17 11-02 11-10
MARSHALLTOWN 31 1955-09-12 28 1896-09-20 10-17 11-02 11-12
HAMPTON-2-NW 32 1955-09-11 28 1955-09-12 10-17 11-02 11-10
MAQUOKETA-2-W 31 1917-09-11 28 1983-09-23 10-17 11-03 11-13
ROCKWELL-CITY 32 1902-09-12 28 1929-09-18 10-17 11-01 11-10
GRINNELL-3-SW 31 1976-09-10 27 1991-09-20 10-17 11-02 11-12
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
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
Iowa - Northeast Climate Division 32 1917-09-11 28 1918-09-21 10-17 11-02 11-11
CHARITON 32 1955-09-12 28 1991-09-20 10-17 11-04 11-20
CORNING 32 1902-09-12 27 1983-09-21 10-17 11-03 11-20
Iowa - West Central Climate Division 31 1902-09-12 28 1913-09-22 10-17 11-02 11-11
RED-OAK 32 1979-09-15 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
WINTERSET 31 1955-09-12 28 1962-09-20 10-18 11-04 11-20
JEFFERSON 32 2011-09-15 23 1974-10-02 10-18 11-04 11-12
CASTANA-EXP-FARM 30 1991-09-19 28 1995-09-22 10-18 11-03 11-12
VINTON 32 1953-09-13 28 1982-09-21 10-18 11-05 11-20
BELLEVUE-L-AND-D-12 31 1956-09-20 25 1995-09-23 10-18 11-05 11-21
ANKENY-3-S 32 1991-09-20 28 1984-09-26 10-18 11-04 11-20
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 11-04 11-20
Allerton 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 11-12
NEWTON 29 1974-09-22 27 1972-09-30 10-18 11-05 11-20
DENISON 29 1902-09-12 21 1918-09-21 10-18 11-02 11-11
Iowa Average 32 1902-09-13 28 1926-09-26 10-18 11-03 11-19
TIPTON 32 1902-09-13 28 1991-09-20 10-18 11-05 11-21
AMES-8-WSW 31 1902-09-13 26 1918-09-21 10-18 11-03 11-12
Lamoni 32 1991-09-19 24 1974-10-02 10-19 11-06 11-21
Iowa - East Central Climate Division 32 1923-09-14 27 1926-09-26 10-19 11-05 11-21
BLOOMFIELD 31 1991-09-20 25 1974-10-02 10-19 11-10 11-21
Iowa - Southwest Climate Division 29 1991-09-19 28 1995-09-22 10-19 11-06 11-21
OSKALOOSA 31 1902-09-13 27 1991-09-20 10-19 11-06 11-21
MOUNT-AYR 32 1902-09-13 28 1991-09-19 10-19 11-05 11-21
SIGOURNEY 31 1995-09-22 28 1964-09-28 10-19 11-07 11-21
BEDFORD-1-NNW 27 1991-09-19 27 1991-09-19 10-19 11-06 11-20
Iowa - Central Climate Division 32 1991-09-19 28 1926-09-26 10-19 11-03 11-19
MOUNT-PLEASANT 29 1991-09-20 25 1974-10-02 10-19 11-10 11-21
CLARINDA 31 1902-09-13 28 1918-09-21 10-19 11-03 11-19
Holstein 31 1991-09-20 28 1984-09-29 10-19 11-06 11-21
GLENWOOD 30 1902-09-12 28 1902-09-13 10-19 11-03 11-19
INDIANOLA-2-SSW 30 1979-09-15 28 1979-09-22 10-19 11-08 11-21
Donnellson 31 1991-09-20 27 1984-09-29 10-19 11-07 11-21
GUTTENBERG-L-AND-D-10 32 1973-09-18 28 1984-09-29 10-19 11-06 11-21
SHENANDOAH-1-NE 30 1980-09-17 26 1983-09-23 10-19 11-07 11-21
GREENFIELD 32 1981-09-17 28 1995-09-22 10-19 11-06 11-20
ONAWA 30 1955-09-11 28 1991-09-19 10-19 11-02 11-11
CLINTON-1 31 1902-09-13 28 1928-09-25 10-20 11-09 11-22
Iowa City 32 1923-09-14 28 1916-09-18 10-20 11-06 11-21
CEDAR-RAPIDS-1 32 2007-09-15 24 1926-09-26 10-20 11-06 11-21
DUBUQUE-LOCK-AND-DAM 28 1956-09-20 28 1956-09-20 10-22 11-06 11-21
Des Moines Airport 31 1995-09-22 26 1942-09-28 10-24 11-08 11-21
Iowa - Southeast Climate Division 32 1902-09-13 25 1942-09-28 10-24 11-09 11-22
WASHINGTON 30 1902-09-13 28 1983-09-23 10-24 11-08 11-21
Ottumwa 32 2007-09-15 23 1942-09-28 10-24 11-08 11-22
FAIRFIELD 32 1917-09-11 28 1918-09-21 10-24 11-08 11-22
Iowa - South Central Climate Division 31 1991-09-19 26 1942-09-28 10-24 11-08 11-21
KEOSAUQUA 31 1917-09-11 28 1916-09-18 10-24 11-09 11-22
MUSCATINE 29 1991-09-20 26 1984-09-29 10-25 11-10 11-24
SIDNEY 30 1991-09-19 28 1995-09-22 10-25 11-08 11-21
Wapello 31 1991-09-20 24 1942-09-28 10-25 11-08 11-21
ALBIA 31 1991-09-19 25 1984-09-29 10-25 11-07 11-21
KNOXVILLE 31 1991-09-19 27 1974-10-02 10-25 11-07 11-21
CENTERVILLE 32 1991-09-19 27 1979-10-05 10-26 11-10 11-24
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 11-28