Iowa Environmental Mesonet

Iowa State University Department of Agronomy

View live 1 minute timeseries from SchoolNet

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:
LEMARS 25 1893-09-02 25 1893-09-02 10-17 10-29 11-08
ROCK-RAPIDS 31 1974-09-03 26 1894-09-10 10-06 10-24 11-03
MARSHALLTOWN 31 1955-09-12 28 1896-09-20 10-17 11-02 11-11
DUBUQUE-LOCK-AND-DAM 31 1956-09-20 24 1899-09-30 10-25 11-10 11-22
GLENWOOD 27 1901-09-18 27 1901-09-18 10-19 11-04 11-21
FAYETTE 32 1949-09-01 27 1902-09-12 10-10 10-28 11-10
ATLANTIC-1-NE 30 1893-09-02 28 1902-09-12 10-17 11-02 11-10
LOGAN 30 1902-09-12 28 1902-09-13 10-18 11-02 11-12
KEOSAUQUA 31 1917-09-11 28 1916-09-18 10-24 11-09 11-22
AMES-8-WSW 31 1902-09-13 26 1918-09-21 10-18 11-02 11-12
CLARINDA 31 1902-09-13 28 1918-09-21 10-19 11-03 11-19
DENISON 29 1902-09-12 21 1918-09-21 10-18 11-02 11-12
FAIRFIELD 32 1917-09-11 28 1918-09-21 10-24 11-08 11-22
MASON-CITY 30 1915-08-30 28 1923-09-14 10-10 11-01 11-08
CLINTON-1 22 1924-08-31 22 1924-08-31 10-19 11-06 11-22
Iowa Average 31 1902-09-13 27 1926-09-26 10-19 11-03 11-19
CEDAR-RAPIDS-1 32 2007-09-15 24 1926-09-26 10-19 11-05 11-21
WEBSTER-CITY 30 1955-09-11 25 1929-09-18 10-13 11-02 11-10
WATERLOO 32 1917-09-11 28 1929-09-18 10-13 11-02 11-10
STORM-LAKE-2-E 32 1902-09-12 28 1929-09-18 10-17 11-02 11-08
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 11-02 11-10
DECORAH-2-N 32 1915-08-30 28 1946-09-02 10-10 11-02 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 10-17 11-03 11-10
CASCADE 32 1955-09-11 28 1953-09-22 10-07 11-03 11-10
OELWEIN-2-S 28 1955-09-11 28 1955-09-11 10-10 11-02 11-10
CHEROKEE 31 1974-09-03 27 1955-09-11 10-07 10-26 11-04
SIBLEY-5-NNE 30 1974-09-03 23 1955-09-11 10-04 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
IOWA-CITY 32 1956-09-20 24 1958-10-01 10-19 11-06 11-21
TOLEDO 31 2007-09-15 28 1962-09-20 10-10 11-03 11-10
WINTERSET 31 1955-09-12 28 1962-09-20 10-18 11-04 11-10
SIGOURNEY 31 1995-09-22 28 1964-09-28 10-19 11-05 11-21
NEWTON 29 1974-09-22 27 1972-09-30 10-18 11-05 11-21
CARROLL-2-SSW 28 1974-09-03 28 1974-09-03 10-07 10-29 11-08
IOWA-FALLS 32 1976-09-10 26 1974-09-22 10-10 11-02 11-07
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
NORTHWOOD 31 1953-09-13 26 1974-09-22 10-09 11-02 11-05
GRUNDY-CENTER 31 2007-09-15 27 1974-09-22 10-07 10-29 11-07
TRIPOLI-4-N 31 2007-09-15 27 1974-09-22 10-10 11-03 11-10
FOREST-CITY 31 2007-09-15 26 1974-09-22 10-09 11-02 11-08
HUMBOLDT-2 32 1976-09-17 26 1974-09-22 10-09 11-02 11-07
CLARION 32 1974-09-03 25 1974-09-22 10-09 10-28 11-07
OSAGE 32 2007-09-15 28 1974-09-22 10-17 11-03 11-10
PERRY 32 1955-09-12 28 1974-09-22 10-09 11-03 11-10
SAC-CITY 32 1974-09-03 27 1974-09-22 10-10 11-02 11-11
Lamoni 32 1991-09-19 24 1974-10-02 10-19 11-05 11-21
Le Claire L&D 14 32 1984-09-29 25 1974-10-02 10-28 11-11 11-24
JEFFERSON 32 2007-09-16 23 1974-10-02 10-18 11-04 11-19
MOUNT-PLEASANT 29 1991-09-20 25 1974-10-02 10-19 11-10 11-21
FORT-MADISON 32 1983-09-23 27 1974-10-02 10-28 11-10 11-24
BLOOMFIELD 31 1991-09-20 25 1974-10-02 10-19 11-05 11-21
KNOXVILLE 31 1991-09-19 27 1974-10-02 10-19 11-07 11-21
INDEPENDENCE-2-W 32 1974-09-03 28 1975-09-13 10-10 11-03 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 10-19 11-05 11-23
Boone 32 1975-09-12 28 1981-09-18 10-10 11-01 11-04
VINTON 32 1953-09-13 28 1982-09-21 10-10 11-03 11-20
POCAHONTAS 30 2007-09-15 28 1983-09-20 10-07 10-28 11-05
CORNING 32 1902-09-12 27 1983-09-21 10-18 11-03 11-19
BRITT 31 2007-09-15 25 1983-09-22 10-09 11-02 11-08
SHENANDOAH-1-NE 30 1980-09-17 26 1983-09-23 10-19 11-05 11-20
MAQUOKETA-2-W 31 1917-09-11 28 1983-09-23 10-17 11-04 11-13
WASHINGTON 30 1902-09-13 28 1983-09-23 10-24 11-08 11-22
MANCHESTER-2 29 2007-09-15 27 1984-09-16 10-07 10-28 11-09
ALLISON 30 1991-09-20 28 1984-09-26 10-18 11-03 11-16
WAUKON 32 1956-09-20 27 1984-09-26 10-10 11-02 11-09
ANKENY-3-S 32 1991-09-20 28 1984-09-26 10-18 11-04 11-20
ALBIA 31 1991-09-19 25 1984-09-29 10-25 11-06 11-21
GUTTENBERG-L-AND-D-10 32 1973-09-18 28 1984-09-29 10-19 11-05 11-21
Ottumwa 29 1981-08-03 27 1984-09-29 10-24 11-08 11-24
MUSCATINE 29 1991-09-20 26 1984-09-29 10-19 11-10 11-24
Des Moines Airport 31 1995-09-22 28 1984-09-29 10-19 11-05 11-20
BEDFORD-1-NNW 27 1991-09-19 27 1991-09-19 10-19 11-04 11-20
Creston 28 1991-09-19 28 1991-09-19 10-18 11-03 11-20
MOUNT-AYR 32 1902-09-13 28 1991-09-19 10-23 11-05 11-21
ONAWA 30 1955-09-11 28 1991-09-19 10-19 11-02 11-11
PRIMGHAR 31 1984-09-15 27 1991-09-19 10-09 11-02 11-08
SIOUX-RAPIDS 31 1974-09-03 28 1991-09-19 10-09 10-29 11-06
HAWARDEN 31 1974-09-03 24 1991-09-19 10-09 10-28 11-04
GUTHRIE-CENTER 31 1893-09-02 28 1991-09-19 10-17 11-02 11-11
AUDUBON 30 1955-09-12 28 1991-09-20 10-10 11-02 11-10
WILLIAMSBURG 31 1955-09-12 28 1991-09-20 10-18 11-04 11-20
CHARLES-CITY 32 1955-09-12 28 1991-09-20 10-10 11-03 11-10
BELLE-PLAINE 32 1955-09-12 28 1991-09-20 10-18 11-04 11-19
GRINNELL-3-SW 31 1976-09-10 27 1991-09-20 10-17 11-03 11-12
CHARITON 32 1955-09-12 28 1991-09-20 10-18 11-04 11-20
TIPTON 32 1902-09-13 28 1991-09-20 10-19 11-05 11-21
CRESCO-1-NE 31 1975-09-13 27 1991-09-20 10-07 10-29 11-05
OSKALOOSA 31 1902-09-13 27 1991-09-20 10-19 11-05 11-21
ESTHERVILLE-2-N 30 2007-09-15 28 1991-09-20 10-07 10-28 11-05
SIOUX-CITY-WSO-AP 32 2007-09-15 25 1995-09-22 10-15 11-02 11-08
FORT-DODGE 32 1974-09-03 28 1995-09-22 10-09 11-02 11-10
RED-OAK 32 1993-09-15 28 1995-09-22 10-18 11-04 11-20
EMMETSBURG 31 1991-09-19 24 1995-09-22 10-10 11-02 11-08
SIDNEY 30 1991-09-19 28 1995-09-22 10-27 11-05 11-24
OAKLAND-2-E 32 1974-09-03 28 1995-09-22 10-10 11-03 11-10
CASTANA-EXP-FARM 30 1991-09-19 28 1995-09-22 10-18 11-03 11-19
GREENFIELD 32 1981-09-17 28 1995-09-22 10-19 11-04 11-20
BELLEVUE-L-AND-D-12 31 1991-09-20 25 1995-09-23 10-18 11-04 11-21
Burlington 32 1991-09-20 26 2003-10-02 10-27 11-10 11-24
Sheldon 32 1974-09-03 28 2007-09-15 10-09 10-28 11-04