Ottumwa 1 WSW Weather Records (USC00136386)
Record envelope, standing records and threshold days for Ottumwa 1 WSW (USC00136386), Iowa, United States, with 56 years of record.
Key Facts for Ottumwa 1 WSW
- Ottumwa 1 WSW (USC00136386) is a weather station in Iowa, United States at 41.02 latitude and -92.43 longitude, 195 m (640 ft) above sea level.
- The station reports from 1894 to 1949, 56 years of record.
- 1,464 records set at Ottumwa 1 WSW still stand.
- Records are tracked for tmax, tmin, prcp, snow: an element needs 30 years of data to be eligible.
- Ottumwa 1 WSW set a daily record high minimum temperature of 15.6 C (60.1 F) on 20 October 1949.
About the Station
- Location: Iowa, United States, 41.02 latitude, -92.43 longitude.
- Elevation: 195 m (640 ft).
- Period of record: 1894 to 1949, 56 years.
- Eligible elements: tmax, tmin, prcp, snow.
Daily Record Envelope and 2026
0 days at or beyond a record| Month | Highest record high | Lowest record low | 2026 highest maximum | 2026 lowest minimum |
|---|---|---|---|---|
| Jan | 20.0 C (68.0 F) | -37.8 C (-36.0 F) | n/a | n/a |
| Feb | 25.6 C (78.1 F) | -33.3 C (-27.9 F) | n/a | n/a |
| Mar | 32.2 C (90.0 F) | -24.4 C (-11.9 F) | n/a | n/a |
| Apr | 35.0 C (95.0 F) | -11.7 C (10.9 F) | n/a | n/a |
| May | 39.4 C (102.9 F) | -3.9 C (25.0 F) | n/a | n/a |
| Jun | 42.2 C (108.0 F) | 2.2 C (36.0 F) | n/a | n/a |
| Jul | 46.1 C (115.0 F) | 7.8 C (46.0 F) | n/a | n/a |
| Aug | 46.1 C (115.0 F) | 4.4 C (39.9 F) | n/a | n/a |
| Sep | 41.7 C (107.1 F) | -5.0 C (23.0 F) | n/a | n/a |
| Oct | 36.1 C (97.0 F) | -15.0 C (5.0 F) | n/a | n/a |
| Nov | 28.3 C (82.9 F) | -22.2 C (-8.0 F) | n/a | n/a |
| Dec | 21.1 C (70.0 F) | -35.6 C (-32.1 F) | n/a | n/a |
Which Years Hold Standing Records
1,464 standing records| Year set | Standing records |
|---|---|
| 1894 | 37 |
| 1895 | 32 |
| 1896 | 28 |
| 1897 | 49 |
| 1898 | 24 |
| 1899 | 30 |
| 1900 | 34 |
| 1901 | 32 |
| 1902 | 39 |
| 1903 | 18 |
| 1904 | 11 |
| 1905 | 19 |
| 1906 | 20 |
| 1907 | 20 |
| 1908 | 20 |
| 1909 | 18 |
| 1910 | 42 |
| 1911 | 38 |
| 1912 | 37 |
| 1913 | 30 |
| 1914 | 22 |
| 1915 | 25 |
| 1916 | 23 |
| 1917 | 44 |
| 1918 | 24 |
| 1919 | 24 |
| 1920 | 24 |
| 1921 | 11 |
| 1922 | 1 |
| 1923 | 20 |
| 1924 | 23 |
| 1925 | 34 |
| 1926 | 20 |
| 1927 | 24 |
| 1928 | 25 |
| 1929 | 22 |
| 1930 | 54 |
| 1931 | 33 |
| 1932 | 19 |
| 1933 | 30 |
| 1934 | 45 |
| 1935 | 19 |
| 1936 | 65 |
| 1937 | 29 |
| 1938 | 23 |
| 1939 | 22 |
| 1940 | 26 |
| 1941 | 17 |
| 1942 | 17 |
| 1943 | 19 |
| 1944 | 18 |
| 1945 | 16 |
| 1946 | 24 |
| 1947 | 22 |
| 1948 | 13 |
| 1949 | 9 |
All-Time Record Progression
3 new records| Date | Kind | Detail |
|---|---|---|
| 1930-01-22 | Record low minimum temperature | Record low minimum temperature -37.8 C (-36.0 F) |
| 1934-07-20 | Record high maximum temperature | Record high maximum temperature 43.9 C (111.0 F) |
| 1934-08-08 | Record high maximum temperature | Record high maximum temperature 46.1 C (115.0 F) |
Wettest Day of Each Month
Oct: 117.6 mm (4.6 in)| Month | Record daily precipitation (mm) | Date |
|---|---|---|
| Jan | 52.1 mm (2.1 in) | 20 January 1904 |
| Feb | 63.5 mm (2.5 in) | 16 February 1911 |
| Mar | 57.9 mm (2.3 in) | 15 March 1919 |
| Apr | 82.6 mm (3.3 in) | 20 April 1905 |
| May | 100.3 mm (3.9 in) | 28 May 1908 |
| Jun | 109.0 mm (4.3 in) | 18 June 1946 |
| Jul | 96.8 mm (3.8 in) | 18 July 1902 |
| Aug | 97.8 mm (3.9 in) | 27 August 1903 |
| Sep | 102.4 mm (4.0 in) | 23 September 1902 |
| Oct | 117.6 mm (4.6 in) | 16 October 1905 |
| Nov | 57.2 mm (2.3 in) | 4 November 1938 |
| Dec | 46.7 mm (1.8 in) | 24 December 1895 |
Period of Record Coverage
1894 to 1949| Year | Days with data | Share of year | Complete |
|---|---|---|---|
| 1894 | 308 | 84% | No |
| 1895 | 292 | 80% | No |
| 1896 | 336 | 92% | Yes |
| 1897 | 348 | 95% | Yes |
| 1898 | 364 | 100% | Yes |
| 1899 | 362 | 99% | Yes |
| 1900 | 348 | 95% | Yes |
| 1901 | 337 | 92% | Yes |
| 1902 | 349 | 96% | Yes |
| 1903 | 315 | 86% | No |
| 1904 | 269 | 73% | No |
| 1905 | 280 | 77% | No |
| 1906 | 351 | 96% | Yes |
| 1907 | 319 | 87% | No |
| 1908 | 346 | 95% | Yes |
| 1909 | 176 | 48% | No |
| 1910 | 363 | 99% | Yes |
| 1911 | 346 | 95% | Yes |
| 1912 | 303 | 83% | No |
| 1913 | 283 | 78% | No |
| 1914 | 258 | 71% | No |
| 1915 | 362 | 99% | Yes |
| 1916 | 365 | 100% | Yes |
| 1917 | 351 | 96% | Yes |
| 1918 | 313 | 86% | No |
| 1919 | 342 | 94% | Yes |
| 1920 | 322 | 88% | No |
| 1921 | 326 | 89% | No |
| 1922 | 61 | 17% | No |
| 1923 | 334 | 92% | Yes |
| 1924 | 366 | 100% | Yes |
| 1925 | 363 | 99% | Yes |
| 1926 | 365 | 100% | Yes |
| 1927 | 363 | 99% | Yes |
| 1928 | 336 | 92% | Yes |
| 1929 | 364 | 100% | Yes |
| 1930 | 365 | 100% | Yes |
| 1931 | 365 | 100% | Yes |
| 1932 | 365 | 100% | Yes |
| 1933 | 364 | 100% | Yes |
| 1934 | 363 | 99% | Yes |
| 1935 | 364 | 100% | Yes |
| 1936 | 366 | 100% | Yes |
| 1937 | 365 | 100% | Yes |
| 1938 | 365 | 100% | Yes |
| 1939 | 365 | 100% | Yes |
| 1940 | 366 | 100% | Yes |
| 1941 | 365 | 100% | Yes |
| 1942 | 365 | 100% | Yes |
| 1943 | 365 | 100% | Yes |
| 1944 | 362 | 99% | Yes |
| 1945 | 360 | 99% | Yes |
| 1946 | 362 | 99% | Yes |
| 1947 | 361 | 99% | Yes |
| 1948 | 362 | 99% | Yes |
| 1949 | 302 | 83% | No |
Latest Records
20| Date | Station | Record | Value | Beat old record by | Old record stood | Significance |
|---|---|---|---|---|---|---|
| 20 October 1949 | Ottumwa 1 WSW, US | daily high min | 15.6 C (60.1 F) | 0.6 C (1.1 F) | 8 years | 8 of 100 (Routine) |
| 10 October 1949 | Ottumwa 1 WSW, US | daily high min (Tie) | 16.7 C (62.1 F) | tie | 31 years | 3 of 100 (Routine) |
| 8 October 1949 | Ottumwa 1 WSW, US | daily high min | 19.4 C (66.9 F) | 2.2 C (4.0 F) | 32 years | 17 of 100 (Routine) |
| 8 September 1949 | Ottumwa 1 WSW, US | daily low min | 6.1 C (43.0 F) | 0.6 C (1.1 F) | 15 years | 10 of 100 (Routine) |
| 1 September 1949 | Ottumwa 1 WSW, US | daily low min | 3.3 C (37.9 F) | 6.1 C (11.0 F) | 30 years | 25 of 100 (Routine) |
| 19 August 1949 | Ottumwa 1 WSW, US | daily rain | 41.1 mm (1.6 in) | 17.0 mm (0.7 in) | 28 years | 24 of 100 (Routine) |
| 24 June 1949 | Ottumwa 1 WSW, US | daily rain | 89.2 mm (3.5 in) | 12.2 mm (0.5 in) | 31 years | 21 of 100 (Routine) |
| 4 May 1949 | Ottumwa 1 WSW, US | daily high min | 20.0 C (68.0 F) | 2.8 C (5.0 F) | 53 years | 26 of 100 (Routine) |
| 3 May 1949 | Ottumwa 1 WSW, US | daily high max (Tie) | 31.1 C (88.0 F) | tie | 20 years | 2 of 100 (Routine) |
| 25 April 1949 | Ottumwa 1 WSW, US | daily high max | 30.6 C (87.1 F) | 1.7 C (3.1 F) | 34 years | 17 of 100 (Routine) |
| 19 April 1949 | Ottumwa 1 WSW, US | daily low min (Tie) | -3.3 C (26.1 F) | tie | 12 years | 2 of 100 (Routine) |
| 15 April 1949 | Ottumwa 1 WSW, US | daily snowfall | 1.3 cm (0.5 in) | 1.0 cm (0.4 in) | 51 years | 20 of 100 (Routine) |
| 15 April 1949 | Ottumwa 1 WSW, US | daily low max | 5.6 C (42.1 F) | 0.5 C (0.9 F) | 44 years | 18 of 100 (Routine) |
| 14 April 1949 | Ottumwa 1 WSW, US | daily rain | 21.3 mm (0.8 in) | 5.0 mm (0.20 in) | 4 years | 10 of 100 (Routine) |
| 30 March 1949 | Ottumwa 1 WSW, US | daily rain | 21.3 mm (0.8 in) | 2.2 mm (0.09 in) | 20 years | 13 of 100 (Routine) |
| 22 March 1949 | Ottumwa 1 WSW, US | daily rain (Tie) | 10.2 mm (0.4 in) | tie | 52 years | 5 of 100 (Routine) |
| 18 February 1949 | Ottumwa 1 WSW, US | daily high min | 5.0 C (41.0 F) | 2.8 C (5.0 F) | 42 years | 20 of 100 (Routine) |
| 13 February 1949 | Ottumwa 1 WSW, US | daily rain | 31.8 mm (1.3 in) | 16.6 mm (0.7 in) | 37 years | 35 of 100 (Notable) |
| 13 February 1949 | Ottumwa 1 WSW, US | daily snowfall | 5.6 cm (2.2 in) | 2.6 cm (1.0 in) | 1 year | 9 of 100 (Routine) |
| 28 January 1949 | Ottumwa 1 WSW, US | daily snowfall | 14.0 cm (5.5 in) | 1.3 cm (0.5 in) | 31 years | 16 of 100 (Routine) |
Climate Trend
33 complete years, 1898 to 1948| Year | Annual mean temperature | Difference from the station mean |
|---|---|---|
| 1898 | 9.8 C | -1.25 C |
| 1900 | 11.8 C | +0.68 C |
| 1902 | 10.6 C | -0.52 C |
| 1906 | 11.0 C | -0.12 C |
| 1908 | 11.2 C | +0.15 C |
| 1910 | 11.6 C | +0.50 C |
| 1915 | 10.9 C | -0.24 C |
| 1916 | 10.7 C | -0.38 C |
| 1917 | 9.1 C | -2.00 C |
| 1924 | 9.8 C | -1.27 C |
| 1925 | 11.1 C | +0.02 C |
| 1926 | 11.0 C | -0.05 C |
| 1927 | 11.4 C | +0.28 C |
| 1929 | 9.7 C | -1.41 C |
| 1930 | 11.5 C | +0.36 C |
| 1931 | 12.7 C | +1.63 C |
| 1932 | 10.7 C | -0.39 C |
| 1933 | 11.8 C | +0.73 C |
| 1934 | 12.3 C | +1.25 C |
| 1935 | 10.8 C | -0.26 C |
| 1936 | 11.1 C | +0.03 C |
| 1937 | 10.1 C | -1.00 C |
| 1938 | 12.2 C | +1.11 C |
| 1939 | 12.1 C | +0.99 C |
| 1940 | 10.4 C | -0.73 C |
| 1941 | 12.4 C | +1.30 C |
| 1942 | 11.5 C | +0.39 C |
| 1943 | 10.9 C | -0.20 C |
| 1944 | 11.4 C | +0.30 C |
| 1945 | 10.2 C | -0.86 C |
| 1946 | 12.2 C | +1.06 C |
| 1947 | 11.1 C | -0.02 C |
| 1948 | 11.1 C | 0.00 C |
The fitted trend in annual mean temperature here over 1898 to 1948 is 0.1 C (-0.1 to 0.4) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: 0.3 F (-0.1 to 0.6) per decade. The slope is a straight line fitted to 33 complete years; the brackets give its 95 percent interval.
| Measure | Per decade (C) | Per decade (F) | Period | Complete years | Reading |
|---|---|---|---|---|---|
| Annual mean temperature | 0.1 C (-0.1 to 0.4) per decade | 0.3 F (-0.1 to 0.6) per decade | 1898 to 1948 | 33 | Not clearly different from zero |
| Mean daily maximum | 0.4 C (0.1 to 0.6) per decade | 0.6 F (0.2 to 1.1) per decade | 1898 to 1948 | 33 | Rise |
| Mean daily minimum | -0.1 C (-0.3 to 0.2) per decade | -0.1 F (-0.5 to 0.3) per decade | 1898 to 1948 | 33 | Not clearly different from zero |
A year is complete when all 12 months have at least 20 days of both daily maximum and daily minimum readings. The annual mean is the mean of the monthly means. The trend describes this one station over this period; it does not say what caused the change.
Extremes by Year
1894 to 1949| Measure | Record | Year of the record | Median year | Years with a value |
|---|---|---|---|---|
| Hottest day (TXx) | 46.1 C (115.0 F) | 1934 | 37.8 C (100.0 F) | 56 |
| Coldest night (TNn) | -37.8 C (-36.0 F) | 1930 | -25.6 C (-14.1 F) | 56 |
| Wettest day (Rx1day) | 117.6 mm (4.6 in) | 1905 | 61.9 mm (2.4 in) | 56 |
| Wettest five days (Rx5day) | 198.9 mm (7.8 in) | 1946 | 97.0 mm (3.8 in) | 56 |
| Longest dry spell (CDD) | 48 days | 1917 | 26 days | 56 |
Hottest day (TXx)
| Year | Hottest day (TXx) |
|---|---|
| 1894 | 39.4 C (102.9 F) |
| 1895 | 36.7 C (98.1 F) |
| 1896 | 36.1 C (97.0 F) |
| 1897 | 38.9 C (102.0 F) |
| 1898 | 37.2 C (99.0 F) |
| 1899 | 38.9 C (102.0 F) |
| 1900 | 36.1 C (97.0 F) |
| 1901 | 42.2 C (108.0 F) |
| 1902 | 33.3 C (91.9 F) |
| 1903 | 37.2 C (99.0 F) |
| 1904 | 35.0 C (95.0 F) |
| 1905 | 37.2 C (99.0 F) |
| 1906 | 36.7 C (98.1 F) |
| 1907 | 37.2 C (99.0 F) |
| 1908 | 38.3 C (100.9 F) |
| 1909 | 30.0 C (86.0 F) |
| 1910 | 39.4 C (102.9 F) |
| 1911 | 43.3 C (109.9 F) |
| 1912 | 40.0 C (104.0 F) |
| 1913 | 41.7 C (107.1 F) |
| 1914 | 37.8 C (100.0 F) |
| 1915 | 35.0 C (95.0 F) |
| 1916 | 40.6 C (105.1 F) |
| 1917 | 38.3 C (100.9 F) |
| 1918 | 42.8 C (109.0 F) |
| 1919 | 37.2 C (99.0 F) |
| 1920 | 36.7 C (98.1 F) |
| 1921 | 35.0 C (95.0 F) |
| 1922 | 21.7 C (71.1 F) |
| 1923 | 37.8 C (100.0 F) |
| 1924 | 36.7 C (98.1 F) |
| 1925 | 39.4 C (102.9 F) |
| 1926 | 36.1 C (97.0 F) |
| 1927 | 37.2 C (99.0 F) |
| 1928 | 35.0 C (95.0 F) |
| 1929 | 36.1 C (97.0 F) |
| 1930 | 42.2 C (108.0 F) |
| 1931 | 40.0 C (104.0 F) |
| 1932 | 36.7 C (98.1 F) |
| 1933 | 39.4 C (102.9 F) |
| 1934 | 46.1 C (115.0 F) |
| 1935 | 40.6 C (105.1 F) |
| 1936 | 46.1 C (115.0 F) |
| 1937 | 39.4 C (102.9 F) |
| 1938 | 38.3 C (100.9 F) |
| 1939 | 38.9 C (102.0 F) |
| 1940 | 41.7 C (107.1 F) |
| 1941 | 40.0 C (104.0 F) |
| 1942 | 37.2 C (99.0 F) |
| 1943 | 36.7 C (98.1 F) |
| 1944 | 36.7 C (98.1 F) |
| 1945 | 37.8 C (100.0 F) |
| 1946 | 36.1 C (97.0 F) |
| 1947 | 40.6 C (105.1 F) |
| 1948 | 39.4 C (102.9 F) |
| 1949 | 35.6 C (96.1 F) |
Coldest night (TNn)
| Year | Coldest night (TNn) |
|---|---|
| 1894 | -28.9 C (-20.0 F) |
| 1895 | -28.9 C (-20.0 F) |
| 1896 | -21.7 C (-7.1 F) |
| 1897 | -27.8 C (-18.0 F) |
| 1898 | -21.7 C (-7.1 F) |
| 1899 | -30.6 C (-23.1 F) |
| 1900 | -21.1 C (-6.0 F) |
| 1901 | -23.9 C (-11.0 F) |
| 1902 | -24.4 C (-11.9 F) |
| 1903 | -22.8 C (-9.0 F) |
| 1904 | -22.2 C (-8.0 F) |
| 1905 | -31.1 C (-24.0 F) |
| 1906 | -17.8 C (0.0 F) |
| 1907 | -22.8 C (-9.0 F) |
| 1908 | -23.9 C (-11.0 F) |
| 1909 | -24.4 C (-11.9 F) |
| 1910 | -26.7 C (-16.1 F) |
| 1911 | -25.0 C (-13.0 F) |
| 1912 | -33.3 C (-27.9 F) |
| 1913 | -27.2 C (-17.0 F) |
| 1914 | -29.4 C (-20.9 F) |
| 1915 | -28.9 C (-20.0 F) |
| 1916 | -28.9 C (-20.0 F) |
| 1917 | -29.4 C (-20.9 F) |
| 1918 | -29.4 C (-20.9 F) |
| 1919 | -27.2 C (-17.0 F) |
| 1920 | -24.4 C (-11.9 F) |
| 1921 | -14.4 C (6.1 F) |
| 1922 | -17.8 C (0.0 F) |
| 1923 | -22.2 C (-8.0 F) |
| 1924 | -35.6 C (-32.1 F) |
| 1925 | -23.9 C (-11.0 F) |
| 1926 | -23.9 C (-11.0 F) |
| 1927 | -27.8 C (-18.0 F) |
| 1928 | -21.7 C (-7.1 F) |
| 1929 | -26.7 C (-16.1 F) |
| 1930 | -37.8 C (-36.0 F) |
| 1931 | -18.3 C (-0.9 F) |
| 1932 | -28.3 C (-18.9 F) |
| 1933 | -28.3 C (-18.9 F) |
| 1934 | -30.6 C (-23.1 F) |
| 1935 | -23.9 C (-11.0 F) |
| 1936 | -33.3 C (-27.9 F) |
| 1937 | -22.2 C (-8.0 F) |
| 1938 | -21.1 C (-6.0 F) |
| 1939 | -22.8 C (-9.0 F) |
| 1940 | -27.2 C (-17.0 F) |
| 1941 | -17.2 C (1.0 F) |
| 1942 | -28.9 C (-20.0 F) |
| 1943 | -27.2 C (-17.0 F) |
| 1944 | -24.4 C (-11.9 F) |
| 1945 | -25.6 C (-14.1 F) |
| 1946 | -21.7 C (-7.1 F) |
| 1947 | -33.3 C (-27.9 F) |
| 1948 | -25.6 C (-14.1 F) |
| 1949 | -27.2 C (-17.0 F) |
Wettest day (Rx1day)
| Year | Wettest day (Rx1day) |
|---|---|
| 1894 | 55.9 mm (2.2 in) |
| 1895 | 53.6 mm (2.1 in) |
| 1896 | 83.6 mm (3.3 in) |
| 1897 | 56.9 mm (2.2 in) |
| 1898 | 69.9 mm (2.8 in) |
| 1899 | 58.9 mm (2.3 in) |
| 1900 | 50.8 mm (2.0 in) |
| 1901 | 38.1 mm (1.5 in) |
| 1902 | 102.4 mm (4.0 in) |
| 1903 | 97.8 mm (3.9 in) |
| 1904 | 78.5 mm (3.1 in) |
| 1905 | 117.6 mm (4.6 in) |
| 1906 | 69.9 mm (2.8 in) |
| 1907 | 80.0 mm (3.1 in) |
| 1908 | 100.3 mm (3.9 in) |
| 1909 | 27.9 mm (1.1 in) |
| 1910 | 62.7 mm (2.5 in) |
| 1911 | 63.5 mm (2.5 in) |
| 1912 | 43.7 mm (1.7 in) |
| 1913 | 94.7 mm (3.7 in) |
| 1914 | 39.9 mm (1.6 in) |
| 1915 | 66.0 mm (2.6 in) |
| 1916 | 55.9 mm (2.2 in) |
| 1917 | 42.4 mm (1.7 in) |
| 1918 | 77.0 mm (3.0 in) |
| 1919 | 61.0 mm (2.4 in) |
| 1920 | 46.7 mm (1.8 in) |
| 1921 | 52.1 mm (2.1 in) |
| 1922 | 12.7 mm (0.5 in) |
| 1923 | 40.6 mm (1.6 in) |
| 1924 | 69.3 mm (2.7 in) |
| 1925 | 55.6 mm (2.2 in) |
| 1926 | 92.7 mm (3.6 in) |
| 1927 | 56.6 mm (2.2 in) |
| 1928 | 67.1 mm (2.6 in) |
| 1929 | 42.4 mm (1.7 in) |
| 1930 | 88.6 mm (3.5 in) |
| 1931 | 94.0 mm (3.7 in) |
| 1932 | 57.9 mm (2.3 in) |
| 1933 | 69.9 mm (2.8 in) |
| 1934 | 41.7 mm (1.6 in) |
| 1935 | 96.5 mm (3.8 in) |
| 1936 | 67.8 mm (2.7 in) |
| 1937 | 53.6 mm (2.1 in) |
| 1938 | 57.4 mm (2.3 in) |
| 1939 | 82.8 mm (3.3 in) |
| 1940 | 55.9 mm (2.2 in) |
| 1941 | 50.5 mm (2.0 in) |
| 1942 | 73.2 mm (2.9 in) |
| 1943 | 54.1 mm (2.1 in) |
| 1944 | 90.9 mm (3.6 in) |
| 1945 | 50.5 mm (2.0 in) |
| 1946 | 109.0 mm (4.3 in) |
| 1947 | 50.5 mm (2.0 in) |
| 1948 | 65.0 mm (2.6 in) |
| 1949 | 89.2 mm (3.5 in) |
Wettest five days (Rx5day)
| Year | Wettest five days (Rx5day) |
|---|---|
| 1894 | 95.8 mm (3.8 in) |
| 1895 | 88.4 mm (3.5 in) |
| 1896 | 114.1 mm (4.5 in) |
| 1897 | 81.3 mm (3.2 in) |
| 1898 | 105.4 mm (4.1 in) |
| 1899 | 70.4 mm (2.8 in) |
| 1900 | 96.5 mm (3.8 in) |
| 1901 | 66.0 mm (2.6 in) |
| 1902 | 130.6 mm (5.1 in) |
| 1903 | 100.1 mm (3.9 in) |
| 1904 | 88.7 mm (3.5 in) |
| 1905 | 171.0 mm (6.7 in) |
| 1906 | 71.6 mm (2.8 in) |
| 1907 | 198.1 mm (7.8 in) |
| 1908 | 121.9 mm (4.8 in) |
| 1909 | 50.0 mm (2.0 in) |
| 1910 | 78.5 mm (3.1 in) |
| 1911 | 97.4 mm (3.8 in) |
| 1912 | 61.8 mm (2.4 in) |
| 1913 | 65.8 mm (2.6 in) |
| 1914 | 56.6 mm (2.2 in) |
| 1915 | 87.3 mm (3.4 in) |
| 1916 | 95.8 mm (3.8 in) |
| 1917 | 88.8 mm (3.5 in) |
| 1918 | 104.2 mm (4.1 in) |
| 1919 | 100.4 mm (4.0 in) |
| 1920 | 68.0 mm (2.7 in) |
| 1921 | 114.6 mm (4.5 in) |
| 1922 | 47.0 mm (1.9 in) |
| 1923 | 67.0 mm (2.6 in) |
| 1924 | 107.9 mm (4.2 in) |
| 1925 | 101.6 mm (4.0 in) |
| 1926 | 137.6 mm (5.4 in) |
| 1927 | 104.9 mm (4.1 in) |
| 1928 | 97.5 mm (3.8 in) |
| 1929 | 77.9 mm (3.1 in) |
| 1930 | 108.5 mm (4.3 in) |
| 1931 | 131.1 mm (5.2 in) |
| 1932 | 137.6 mm (5.4 in) |
| 1933 | 84.7 mm (3.3 in) |
| 1934 | 72.7 mm (2.9 in) |
| 1935 | 179.8 mm (7.1 in) |
| 1936 | 134.6 mm (5.3 in) |
| 1937 | 69.3 mm (2.7 in) |
| 1938 | 131.1 mm (5.2 in) |
| 1939 | 167.6 mm (6.6 in) |
| 1940 | 83.6 mm (3.3 in) |
| 1941 | 74.7 mm (2.9 in) |
| 1942 | 92.5 mm (3.6 in) |
| 1943 | 103.3 mm (4.1 in) |
| 1944 | 106.4 mm (4.2 in) |
| 1945 | 100.4 mm (4.0 in) |
| 1946 | 198.9 mm (7.8 in) |
| 1947 | 85.3 mm (3.4 in) |
| 1948 | 83.8 mm (3.3 in) |
| 1949 | 117.6 mm (4.6 in) |
Longest dry spell (CDD)
| Year | Longest dry spell (CDD) |
|---|---|
| 1894 | 30 days |
| 1895 | 20 days |
| 1896 | 21 days |
| 1897 | 25 days |
| 1898 | 25 days |
| 1899 | 19 days |
| 1900 | 31 days |
| 1901 | 25 days |
| 1902 | 24 days |
| 1903 | 31 days |
| 1904 | 31 days |
| 1905 | 27 days |
| 1906 | 27 days |
| 1907 | 23 days |
| 1908 | 26 days |
| 1909 | 11 days |
| 1910 | 30 days |
| 1911 | 29 days |
| 1912 | 30 days |
| 1913 | 38 days |
| 1914 | 29 days |
| 1915 | 30 days |
| 1916 | 36 days |
| 1917 | 48 days |
| 1918 | 18 days |
| 1919 | 25 days |
| 1920 | 22 days |
| 1921 | 16 days |
| 1922 | 13 days |
| 1923 | 14 days |
| 1924 | 22 days |
| 1925 | 26 days |
| 1926 | 26 days |
| 1927 | 34 days |
| 1928 | 34 days |
| 1929 | 17 days |
| 1930 | 29 days |
| 1931 | 18 days |
| 1932 | 30 days |
| 1933 | 30 days |
| 1934 | 35 days |
| 1935 | 17 days |
| 1936 | 23 days |
| 1937 | 19 days |
| 1938 | 24 days |
| 1939 | 37 days |
| 1940 | 20 days |
| 1941 | 18 days |
| 1942 | 34 days |
| 1943 | 27 days |
| 1944 | 28 days |
| 1945 | 38 days |
| 1946 | 22 days |
| 1947 | 27 days |
| 1948 | 32 days |
| 1949 | 23 days |
Each chart shows one value per year; the dot marks the record year. TXx is the hottest daily maximum, TNn the coldest daily minimum, Rx1day and Rx5day the largest one-day and five-day rain totals, and CDD the longest run of days with less than 1 mm of rain. A year with missing days can understate an extreme.
Frost Dates and Growing Season
33 years with a frostAcross 33 years with a frost, the median last spring frost at Ottumwa 1 WSW falls on 25 April and the median first autumn frost on 10 October, which leaves a median of 170 days between them.
Fitted over all years, the growing season changes by -2.1 days per decade at this station.
| Measure | Median, all years | Earliest period | Recent period (1906 to 1948) | Recent against earliest | Fitted trend |
|---|---|---|---|---|---|
| Last spring frost | 25 April | n/a | 27 April | n/a | +0.5 days per decade |
| First autumn frost | 10 October | n/a | 10 October | n/a | -1.5 days per decade |
| Growing days | 170 days | n/a | 168 days | n/a | -2.1 days per decade |
A frost day is a day with a daily minimum at or below 0 C (32 F). The last spring frost and the first autumn frost are the last and first such days of the cold season, and growing days are the days between them. A negative trend for the last spring frost means it comes earlier.
Rainfall Return Levels
38 years, 1894 to 1948A day with at least 62.0 mm (2.4 in) of rain is expected about once in 2 years. A day with at least 126.5 mm (5.0 in) of rain is expected about once in 100 years.
| Expected about once in | A day with at least | Note |
|---|---|---|
| 2 years | 62.0 mm (2.4 in) | |
| 5 years | 78.7 mm (3.1 in) | |
| 10 years | 90.1 mm (3.5 in) | |
| 25 years | 104.6 mm (4.1 in) | |
| 50 years | 115.5 mm (4.5 in) | Longer than the 38 years of record |
| 100 years | 126.5 mm (5.0 in) | Longer than the 38 years of record |
The levels come from a generalised extreme value (GEV) distribution fitted by L-moments to the wettest-day total of each year, 38 years of values from 1894 to 1948.
A return level is an estimate. It is least reliable for the long periods, 50 and 100 years, and for any period longer than the record behind the fit, where the fit has to reach past the largest day actually observed. It is not a forecast.
The largest wettest-day totals in the fit: 109.0 mm (4.3 in) in 1946; 102.4 mm (4.0 in) in 1902; 96.5 mm (3.8 in) in 1935.
Download the Data
Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-17 (17 October 2026). Records are computed by this site and are not official.
Data as of . Last revised (2025-12-31).