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