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
MARSHALLTOWN 31 1955-09-12 28 1896-09-20 10-17 11-02 11-12
ATLANTIC-1-NE 30 1893-09-02 28 1902-09-12 10-17 11-02 11-10
FAYETTE 32 1949-09-01 27 1902-09-12 10-10 10-28 11-10
LEMARS 31 1955-09-11 28 1902-09-12 10-13 10-29 11-08
Iowa - Northwest Climate Division 32 1974-09-03 27 1902-09-13 10-10 10-28 11-08
GLENWOOD 30 1902-09-12 28 1902-09-13 10-19 11-03 11-19
LOGAN 30 1902-09-12 28 1902-09-13 10-18 11-02 11-12
Iowa - West Central Climate Division 31 1902-09-12 28 1913-09-22 10-17 11-02 11-11
Iowa City 32 1923-09-14 28 1916-09-18 10-20 11-06 11-21
KEOSAUQUA 31 1917-09-11 28 1916-09-18 10-24 11-09 11-22
DENISON 29 1902-09-12 21 1918-09-21 10-18 11-02 11-11
AMES-8-WSW 31 1902-09-13 26 1918-09-21 10-18 11-03 11-12
FAIRFIELD 32 1917-09-11 28 1918-09-21 10-24 11-08 11-22
CLARINDA 31 1902-09-13 28 1918-09-21 10-19 11-03 11-19
Iowa - Northeast Climate Division 32 1917-09-11 28 1918-09-21 10-17 11-02 11-11
MASON-CITY 30 1915-08-30 28 1923-09-14 10-10 11-01 11-09
Iowa Average 32 1902-09-13 28 1926-09-26 10-18 11-03 11-19
Iowa - Central Climate Division 32 1991-09-19 28 1926-09-26 10-19 11-03 11-19
CEDAR-RAPIDS-1 32 2007-09-15 24 1926-09-26 10-20 11-06 11-21
Iowa - East Central Climate Division 32 1923-09-14 27 1926-09-26 10-19 11-05 11-21
CLINTON-1 31 1902-09-13 28 1928-09-25 10-20 11-09 11-22
WEBSTER-CITY 30 1955-09-11 25 1929-09-18 10-13 11-01 11-10
STORM-LAKE-2-E 32 1902-09-12 28 1929-09-18 10-13 11-02 11-10
WATERLOO 32 1917-09-11 28 1929-09-18 10-13 11-02 11-11
ALGONA 29 1893-09-02 27 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
Iowa - Southeast Climate Division 32 1902-09-13 25 1942-09-28 10-24 11-09 11-22
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
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
DECORAH-2-N 32 1915-08-30 28 1946-09-02 10-10 11-01 11-10
NEW-HAMPTON 28 1949-09-01 28 1949-09-01 10-17 11-02 11-10
HARLAN 29 1991-09-19 27 1951-09-28 10-16 11-03 11-11
CASCADE 32 1955-09-11 28 1953-09-22 10-07 11-03 11-12
CHEROKEE 31 1974-09-03 27 1955-09-11 10-07 10-26 11-04
OELWEIN-2-S 28 1955-09-11 28 1955-09-11 10-10 11-02 11-10
SIBLEY-5-NNE 30 1974-09-03 23 1955-09-11 10-07 10-26 11-03
HAMPTON-2-NW 32 1955-09-11 28 1955-09-12 10-17 11-02 11-10
ANAMOSA-1-WNW 29 1955-09-12 27 1956-09-20 10-10 11-03 11-12
DUBUQUE-LOCK-AND-DAM 28 1956-09-20 28 1956-09-20 10-22 11-06 11-21
WINTERSET 31 1955-09-12 28 1962-09-20 10-18 11-04 11-20
AUDUBON 30 1955-09-12 28 1962-09-20 10-10 11-01 11-10
TOLEDO 31 2007-09-15 28 1962-09-20 10-10 11-03 11-12
SIGOURNEY 31 1995-09-22 28 1964-09-28 10-19 11-07 11-21
NEWTON 29 1974-09-22 27 1972-09-30 10-18 11-05 11-20
CARROLL-2-SSW 28 1974-09-03 28 1974-09-03 10-10 10-28 11-10
PERRY 32 1955-09-12 28 1974-09-22 10-10 11-02 11-11
NORTHWOOD 31 1953-09-13 26 1974-09-22 10-10 10-28 11-08
GRUNDY-CENTER 31 2007-09-15 27 1974-09-22 10-10 10-29 11-10
OSAGE 32 2007-09-15 28 1974-09-22 10-10 11-02 11-11
CLARION 32 1974-09-03 25 1974-09-22 10-09 10-28 11-09
Iowa - North Central Climate Division 30 2011-09-15 26 1974-09-22 10-17 11-02 11-10
SAC-CITY 32 1974-09-03 27 1974-09-22 10-10 11-01 11-11
FOREST-CITY 30 2011-09-15 26 1974-09-22 10-10 10-28 11-10
OSCEOLA-3-WSW 31 2007-09-15 28 1974-09-22 10-18 11-04 11-20
Eldora 32 1962-09-20 28 1974-09-22 10-10 11-03 11-10
TRIPOLI-4-N 31 2007-09-15 27 1974-09-22 10-10 11-02 11-12
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
HUMBOLDT-2 31 2011-09-15 26 1974-09-22 10-10 11-02 11-10
BLOOMFIELD 31 1991-09-20 25 1974-10-02 10-19 11-10 11-21
Lamoni 32 1991-09-19 24 1974-10-02 10-19 11-06 11-21
JEFFERSON 32 2011-09-15 23 1974-10-02 10-18 11-04 11-12
Fort Madison 32 1983-09-23 27 1974-10-02 10-28 11-19 11-28
MOUNT-PLEASANT 29 1991-09-20 25 1974-10-02 10-19 11-10 11-21
KNOXVILLE 31 1991-09-19 27 1974-10-02 10-25 11-07 11-21
Le Claire L&D 14 32 1984-09-29 25 1974-10-02 10-28 11-11 11-24
INDEPENDENCE-2-W 32 1974-09-03 28 1975-09-13 10-10 10-29 11-10
INDIANOLA-2-SSW 30 1979-09-15 28 1979-09-22 10-19 11-08 11-21
CENTERVILLE 32 1991-09-19 27 1979-10-05 10-26 11-10 11-24
Boone 32 1975-09-12 28 1981-09-18 10-10 11-03 11-11
VINTON 32 1953-09-13 28 1982-09-21 10-18 11-05 11-20
POCAHONTAS 32 2014-09-13 28 1983-09-20 10-10 10-28 11-07
CORNING 32 1902-09-12 27 1983-09-21 10-17 11-03 11-20
Milford 32 1974-09-03 27 1983-09-21 10-10 10-31 11-07
BRITT 31 2007-09-15 25 1983-09-22 10-09 10-28 11-10
SHENANDOAH-1-NE 30 1980-09-17 26 1983-09-23 10-19 11-07 11-21
WASHINGTON 30 1902-09-13 28 1983-09-23 10-24 11-08 11-21
MAQUOKETA-2-W 31 1917-09-11 28 1983-09-23 10-17 11-03 11-13
MANCHESTER-2 32 2014-09-13 27 1984-09-16 10-07 10-28 11-10
ALLISON 30 1991-09-20 28 1984-09-26 10-18 11-03 11-12
ANKENY-3-S 32 1991-09-20 28 1984-09-26 10-18 11-04 11-20
WAUKON 32 2011-09-16 27 1984-09-26 10-16 11-02 11-10
ALBIA 31 1991-09-19 25 1984-09-29 10-25 11-07 11-21
Holstein 31 1991-09-20 28 1984-09-29 10-19 11-06 11-21
GUTTENBERG-L-AND-D-10 32 1973-09-18 28 1984-09-29 10-19 11-06 11-21
Donnellson 31 1991-09-20 27 1984-09-29 10-19 11-07 11-21
Allerton 31 1991-09-19 27 1984-09-29 10-18 11-05 11-21
MUSCATINE 29 1991-09-20 26 1984-09-29 10-25 11-10 11-24
SIOUX-RAPIDS 31 1974-09-03 28 1991-09-19 10-09 10-28 11-07
ONAWA 30 1955-09-11 28 1991-09-19 10-19 11-02 11-11
MOUNT-AYR 32 1902-09-13 28 1991-09-19 10-19 11-05 11-21
GUTHRIE-CENTER 31 1893-09-02 28 1991-09-19 10-17 11-02 11-11
HAWARDEN 31 1974-09-03 24 1991-09-19 10-09 10-28 11-04
Creston 28 1991-09-19 28 1991-09-19 10-18 11-04 11-20
PRIMGHAR 31 1984-09-15 27 1991-09-19 10-16 11-02 11-10
BEDFORD-1-NNW 27 1991-09-19 27 1991-09-19 10-19 11-06 11-20
GRINNELL-3-SW 31 1976-09-10 27 1991-09-20 10-17 11-02 11-12
CHARLES-CITY 32 1955-09-12 28 1991-09-20 10-10 11-03 11-12
CRESCO-1-NE 31 1975-09-13 27 1991-09-20 10-05 10-28 11-07
OSKALOOSA 31 1902-09-13 27 1991-09-20 10-19 11-06 11-21
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 11-19
WILLIAMSBURG 31 1955-09-12 28 1991-09-20 10-17 11-04 11-20
TIPTON 32 1902-09-13 28 1991-09-20 10-18 11-05 11-21
ESTHERVILLE-2-N 32 2014-09-13 28 1991-09-20 10-07 10-28 11-07
RED-OAK 32 1979-09-15 28 1995-09-22 10-18 11-04 11-20
SIOUX-CITY-WSO-AP 30 1902-09-13 25 1995-09-22 10-17 11-02 11-10
OAKLAND-2-E 32 1974-09-03 28 1995-09-22 10-16 11-03 11-12
Emmetsburg 32 2011-09-15 24 1995-09-22 10-10 11-01 11-10
GREENFIELD 32 1981-09-17 28 1995-09-22 10-19 11-06 11-20
SIDNEY 30 1991-09-19 28 1995-09-22 10-25 11-08 11-21
Iowa - Southwest Climate Division 29 1991-09-19 28 1995-09-22 10-19 11-06 11-21
CASTANA-EXP-FARM 30 1991-09-19 28 1995-09-22 10-18 11-03 11-12
BELLEVUE-L-AND-D-12 31 1956-09-20 25 1995-09-23 10-18 11-05 11-21
Elkader 6SSW (Osborn) 32 1893-08-29 0 2002-09-02 10-09 10-28 11-10
Burlington 32 1991-09-20 26 2003-10-02 10-27 11-10 11-24
Sheldon 32 1974-09-03 28 2007-09-15 10-07 10-27 11-04
Spencer 31 1974-09-03 28 2007-09-15 10-09 10-27 11-03