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: |
| Albia | 31 | 1991-09-19 | 25 | 1984-09-29 | 10-25 | 11-06 | 11-21 |
| Algona | 29 | 1893-09-02 | 27 | 1929-09-18 | 10-17 | 11-02 | 11-10 |
| Allerton | 31 | 1991-09-19 | 27 | 1984-09-29 | 10-18 | 11-05 | 11-18 |
| Allison | 30 | 1991-09-20 | 28 | 1984-09-26 | 10-18 | 11-03 | 11-16 |
| Ames | 31 | 1902-09-13 | 26 | 1918-09-21 | 10-18 | 11-02 | 11-12 |
| Anamosa | 29 | 1955-09-12 | 27 | 1956-09-20 | 10-10 | 11-03 | 11-12 |
| Ankeny | 32 | 1991-09-20 | 28 | 1984-09-26 | 10-18 | 11-04 | 11-20 |
| Atlantic | 30 | 1893-09-02 | 28 | 1902-09-12 | 10-17 | 11-02 | 11-10 |
| Audubon | 30 | 1955-09-12 | 28 | 1991-09-20 | 10-10 | 11-02 | 11-10 |
| Bedford | 27 | 1991-09-19 | 27 | 1991-09-19 | 10-19 | 11-04 | 11-20 |
| Belle-plaine | 32 | 1955-09-12 | 28 | 1991-09-20 | 10-18 | 11-04 | 11-19 |
| Bellevue | 31 | 1991-09-20 | 25 | 1995-09-23 | 10-18 | 11-04 | 11-21 |
| Bloomfield | 31 | 1991-09-20 | 25 | 1974-10-02 | 10-19 | 11-05 | 11-21 |
| Boone | 32 | 1975-09-12 | 28 | 1981-09-18 | 10-10 | 11-01 | 11-04 |
| Britt | 31 | 2007-09-15 | 25 | 1983-09-22 | 10-09 | 11-02 | 11-08 |
| Burlington | 32 | 1991-09-20 | 26 | 2003-10-02 | 10-25 | 11-10 | 11-24 |
| Carroll | 28 | 1974-09-03 | 28 | 1974-09-03 | 10-07 | 10-29 | 11-08 |
| Cascade | 32 | 1955-09-11 | 28 | 1953-09-22 | 10-07 | 11-03 | 11-10 |
| Castana | 30 | 1991-09-19 | 28 | 1995-09-22 | 10-18 | 11-03 | 11-19 |
| Cedar Rapids | 32 | 2007-09-15 | 24 | 1926-09-26 | 10-19 | 11-05 | 11-21 |
| Centerville | 32 | 1991-09-19 | 27 | 1979-10-05 | 10-19 | 11-05 | 11-23 |
| Chariton | 32 | 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 |
| Cherokee | 31 | 1974-09-03 | 27 | 1955-09-11 | 10-07 | 10-26 | 11-04 |
| Clarinda | 31 | 1902-09-13 | 28 | 1918-09-21 | 10-19 | 11-03 | 11-19 |
| Clarion | 32 | 1974-09-03 | 25 | 1974-09-22 | 10-09 | 10-28 | 11-07 |
| Clinton | 22 | 1924-08-31 | 22 | 1924-08-31 | 10-19 | 11-06 | 11-22 |
| Colombus Junction | 31 | 1955-09-12 | 28 | 1991-09-20 | 10-19 | 11-05 | 11-21 |
| Corning | 32 | 1902-09-12 | 27 | 1983-09-21 | 10-18 | 11-03 | 11-19 |
| Cresco | 31 | 1975-09-13 | 27 | 1991-09-20 | 10-07 | 10-29 | 11-05 |
| Creston | 28 | 1991-09-19 | 28 | 1991-09-19 | 10-18 | 11-03 | 11-20 |
| Decorah | 32 | 1915-08-30 | 28 | 1946-09-02 | 10-10 | 11-02 | 11-10 |
| Denison | 29 | 1902-09-12 | 21 | 1918-09-21 | 10-18 | 11-02 | 11-12 |
| Des Moines | 31 | 1995-09-22 | 28 | 1984-09-29 | 10-19 | 11-05 | 11-20 |
| Dubuque | 31 | 1956-09-20 | 28 | 1952-10-06 | 10-28 | 11-10 | 11-24 |
| Emmetsburg | 31 | 1991-09-19 | 24 | 1995-09-22 | 10-10 | 11-02 | 11-08 |
| Estherville | 30 | 2007-09-15 | 28 | 1991-09-20 | 10-07 | 10-28 | 11-05 |
| Fairfield | 32 | 1917-09-11 | 28 | 1918-09-21 | 10-24 | 11-08 | 11-22 |
| Fayette | 32 | 1949-09-01 | 27 | 1902-09-12 | 10-10 | 10-28 | 11-10 |
| Forest City | 31 | 2007-09-15 | 26 | 1974-09-22 | 10-09 | 11-02 | 11-08 |
| Fort Dodge | 32 | 1974-09-03 | 28 | 1995-09-22 | 10-09 | 11-02 | 11-10 |
| Fort Madison | 32 | 1983-09-23 | 27 | 1974-10-02 | 10-28 | 11-10 | 11-24 |
| Glenwood | 27 | 1901-09-18 | 27 | 1901-09-18 | 10-19 | 11-04 | 11-21 |
| Greenfield | 32 | 1981-09-17 | 28 | 1995-09-22 | 10-19 | 11-04 | 11-20 |
| Grinnell | 31 | 1976-09-10 | 27 | 1991-09-20 | 10-17 | 11-03 | 11-12 |
| Grundy Center | 31 | 2007-09-15 | 27 | 1974-09-22 | 10-07 | 10-29 | 11-07 |
| Guthrie Center | 31 | 1893-09-02 | 28 | 1991-09-19 | 10-17 | 11-02 | 11-11 |
| Guttenburg | 32 | 1973-09-18 | 28 | 1984-09-29 | 10-19 | 11-05 | 11-21 |
| Hampton | 32 | 1955-09-11 | 28 | 1955-09-12 | 10-12 | 11-02 | 11-10 |
| Harlan | 29 | 1991-09-19 | 27 | 1951-09-28 | 10-17 | 11-03 | 11-10 |
| Hawarden | 31 | 1974-09-03 | 24 | 1991-09-19 | 10-09 | 10-28 | 11-04 |
| Humboldt | 32 | 1976-09-17 | 26 | 1974-09-22 | 10-09 | 11-02 | 11-07 |
| Ida Grove | 32 | 1974-09-03 | 28 | 1962-09-20 | 10-09 | 10-28 | 11-04 |
| Independence | 32 | 1974-09-03 | 28 | 1975-09-13 | 10-10 | 11-03 | 11-10 |
| Indianola | 30 | 1979-09-15 | 28 | 1979-09-22 | 10-19 | 11-08 | 11-21 |
| Iowa City | 32 | 1956-09-20 | 24 | 1958-10-01 | 10-19 | 11-06 | 11-21 |
| Iowa Falls | 32 | 1976-09-10 | 26 | 1974-09-22 | 10-10 | 11-02 | 11-07 |
| Jefferson | 32 | 2007-09-16 | 23 | 1974-10-02 | 10-18 | 11-04 | 11-19 |
| Keosauqua | 31 | 1917-09-11 | 28 | 1916-09-18 | 10-24 | 11-09 | 11-22 |
| Knoxville | 31 | 1991-09-19 | 27 | 1974-10-02 | 10-19 | 11-07 | 11-21 |
| Lamoni | 32 | 1991-09-19 | 24 | 1974-10-02 | 10-18 | 11-05 | 11-21 |
| Le Claire L&D 14 | 32 | 1984-09-29 | 25 | 1974-10-02 | 10-28 | 11-11 | 11-24 |
| Lemars | 25 | 1893-09-02 | 25 | 1893-09-02 | 10-17 | 10-29 | 11-08 |
| Logan | 30 | 1902-09-12 | 28 | 1902-09-13 | 10-18 | 11-02 | 11-12 |
| Manchester | 29 | 2007-09-15 | 27 | 1984-09-16 | 10-07 | 10-28 | 11-09 |
| Maquoketa | 31 | 1917-09-11 | 28 | 1983-09-23 | 10-17 | 11-04 | 11-13 |
| Marshalltown | 31 | 1955-09-12 | 28 | 1896-09-20 | 10-17 | 11-02 | 11-11 |
| Mason City | 30 | 1915-08-30 | 28 | 1923-09-14 | 10-10 | 11-01 | 11-08 |
| Milford | 32 | 1974-09-03 | 27 | 1983-09-21 | 10-09 | 10-29 | 11-04 |
| Mount Ayr | 32 | 1902-09-13 | 28 | 1991-09-19 | 10-23 | 11-05 | 11-21 |
| Mount Pleasant | 29 | 1991-09-20 | 25 | 1974-10-02 | 10-19 | 11-10 | 11-21 |
| Muscatine | 29 | 1991-09-20 | 26 | 1984-09-29 | 10-19 | 11-10 | 11-24 |
| New Hampton | 28 | 1949-09-01 | 28 | 1949-09-01 | 10-17 | 11-02 | 11-10 |
| Newton | 29 | 1974-09-22 | 27 | 1972-09-30 | 10-18 | 11-05 | 11-21 |
| Northwood | 31 | 1953-09-13 | 26 | 1974-09-22 | 10-09 | 11-02 | 11-05 |
| Oakland | 32 | 1974-09-03 | 28 | 1995-09-22 | 10-10 | 11-03 | 11-10 |
| Oelwein | 28 | 1955-09-11 | 28 | 1955-09-11 | 10-10 | 11-02 | 11-10 |
| Onawa | 30 | 1955-09-11 | 28 | 1991-09-19 | 10-19 | 11-02 | 11-11 |
| Osage | 32 | 2007-09-15 | 28 | 1974-09-22 | 10-17 | 11-03 | 11-10 |
| Osceola | 31 | 2007-09-15 | 28 | 1974-09-22 | 10-18 | 11-04 | 11-20 |
| Oskaloosa | 31 | 1902-09-13 | 27 | 1991-09-20 | 10-19 | 11-05 | 11-21 |
| Ottumwa | 29 | 1981-08-03 | 27 | 1984-09-29 | 10-24 | 11-08 | 11-24 |
| Perry | 32 | 1955-09-12 | 28 | 1974-09-22 | 10-09 | 11-03 | 11-10 |
| Pocahontas | 30 | 2007-09-15 | 28 | 1983-09-20 | 10-07 | 10-28 | 11-05 |
| Primghar | 31 | 1984-09-15 | 27 | 1991-09-19 | 10-09 | 11-02 | 11-08 |
| Red Oak | 32 | 1993-09-15 | 28 | 1995-09-22 | 10-18 | 11-04 | 11-20 |
| Rock Rapids | 31 | 1974-09-03 | 26 | 1894-09-10 | 10-06 | 10-24 | 11-03 |
| Rockwell City | 32 | 1902-09-12 | 28 | 1929-09-18 | 10-17 | 11-02 | 11-10 |
| Sac City | 32 | 1974-09-03 | 27 | 1974-09-22 | 10-10 | 11-02 | 11-11 |
| Shenandoah | 30 | 1980-09-17 | 26 | 1983-09-23 | 10-19 | 11-05 | 11-20 |
| Sibley | 30 | 1974-09-03 | 23 | 1955-09-11 | 10-04 | 10-26 | 11-03 |
| Sidney | 30 | 1991-09-19 | 28 | 1995-09-22 | 10-27 | 11-05 | 11-24 |
| Sigourney | 31 | 1995-09-22 | 28 | 1964-09-28 | 10-19 | 11-05 | 11-21 |
| Sioux City | 32 | 2007-09-15 | 25 | 1995-09-22 | 10-10 | 11-02 | 11-08 |
| Sioux Rapids | 31 | 1974-09-03 | 28 | 1991-09-19 | 10-09 | 10-29 | 11-06 |
| Storm Lake | 32 | 1902-09-12 | 28 | 1929-09-18 | 10-17 | 11-02 | 11-08 |
| Tipton | 32 | 1902-09-13 | 28 | 1991-09-20 | 10-19 | 11-05 | 11-21 |
| Toledo | 31 | 2007-09-15 | 28 | 1962-09-20 | 10-10 | 11-03 | 11-10 |
| Tripoli | 31 | 2007-09-15 | 27 | 1974-09-22 | 10-10 | 11-03 | 11-10 |
| Vinton | 32 | 1953-09-13 | 28 | 1982-09-21 | 10-10 | 11-03 | 11-20 |
| Washington | 30 | 1902-09-13 | 28 | 1983-09-23 | 10-24 | 11-08 | 11-22 |
| Waterloo | 32 | 1917-09-11 | 28 | 1929-09-18 | 10-13 | 11-02 | 11-10 |
| Waukon | 32 | 1956-09-20 | 27 | 1984-09-26 | 10-10 | 11-02 | 11-09 |
| Webster City | 30 | 1955-09-11 | 25 | 1929-09-18 | 10-13 | 11-02 | 11-10 |
| Williamsburg | 31 | 1955-09-12 | 28 | 1991-09-20 | 10-18 | 11-04 | 11-20 |
| Winterset | 31 | 1955-09-12 | 28 | 1962-09-20 | 10-18 | 11-04 | 11-10 |
