| Climate data for Des Moines International Airport, Iowa (1991–2020 normals,[a] extremes 1878–present[b]) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °F (°C) | 67 (19) |
78 (26) |
91 (33) |
93 (34) |
105 (41) |
103 (39) |
110 (43) |
110 (43) |
101 (38) |
95 (35) |
82 (28) |
74 (23) |
110 (43) |
| Mean maximum °F (°C) | 53.4 (11.9) |
58.7 (14.8) |
74.6 (23.7) |
83.9 (28.8) |
88.9 (31.6) |
93.1 (33.9) |
96.2 (35.7) |
94.4 (34.7) |
91.3 (32.9) |
83.3 (28.5) |
70.4 (21.3) |
57.8 (14.3) |
97.4 (36.3) |
| Mean daily maximum °F (°C) | 30.9 (−0.6) |
35.7 (2.1) |
49.2 (9.6) |
62.0 (16.7) |
72.4 (22.4) |
81.9 (27.7) |
85.6 (29.8) |
83.6 (28.7) |
76.9 (24.9) |
63.4 (17.4) |
48.3 (9.1) |
35.9 (2.2) |
60.5 (15.8) |
| Daily mean °F (°C) | 22.3 (−5.4) |
26.9 (−2.8) |
39.4 (4.1) |
51.3 (10.7) |
62.4 (16.9) |
72.2 (22.3) |
76.0 (24.4) |
73.9 (23.3) |
66.2 (19.0) |
53.2 (11.8) |
39.3 (4.1) |
27.7 (−2.4) |
50.9 (10.5) |
| Mean daily minimum °F (°C) | 13.8 (−10.1) |
18.0 (−7.8) |
29.6 (−1.3) |
40.6 (4.8) |
52.3 (11.3) |
62.4 (16.9) |
66.4 (19.1) |
64.2 (17.9) |
55.4 (13.0) |
42.9 (6.1) |
30.2 (−1.0) |
19.5 (−6.9) |
41.3 (5.2) |
| Mean minimum °F (°C) | −7.8 (−22.1) |
−2.7 (−19.3) |
9.2 (−12.7) |
24.9 (−3.9) |
37.6 (3.1) |
50.2 (10.1) |
56.9 (13.8) |
54.8 (12.7) |
40.4 (4.7) |
26.8 (−2.9) |
12.6 (−10.8) |
−1.2 (−18.4) |
−11.4 (−24.1) |
| Record low °F (°C) | −30 (−34) |
−26 (−32) |
−22 (−30) |
9 (−13) |
26 (−3) |
37 (3) |
47 (8) |
40 (4) |
26 (−3) |
7 (−14) |
−10 (−23) |
−22 (−30) |
−30 (−34) |
| Average precipitation inches (mm) | 1.08 (27) |
1.34 (34) |
2.17 (55) |
4.02 (102) |
5.24 (133) |
5.26 (134) |
3.82 (97) |
4.17 (106) |
3.18 (81) |
2.78 (71) |
1.91 (49) |
1.58 (40) |
36.55 (928) |
| Average snowfall inches (cm) | 9.4 (24) |
10.2 (26) |
4.4 (11) |
1.2 (3.0) |
0.2 (0.51) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.5 (1.3) |
2.7 (6.9) |
7.9 (20) |
36.5 (93) |
| Average extreme snow depth inches (cm) | 7 (18) |
7 (18) |
4 (10) |
1 (2.5) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
2 (5.1) |
5 (13) |
7 (18) |
| Average precipitation days (≥ 0.01 in) | 8.2 | 8.4 | 9.5 | 11.5 | 12.7 | 11.7 | 9.5 | 9.4 | 8.2 | 8.6 | 7.7 | 7.8 | 113.2 |
| Average snowy days (≥ 0.1 in) | 6.9 | 6.3 | 3.1 | 1.0 | 0.1 | 0.0 | 0.0 | 0.0 | 0.0 | 0.5 | 1.8 | 5.6 | 25.3 |
| Average relative humidity (%) | 71.0 | 71.3 | 67.9 | 63.2 | 63.0 | 64.8 | 67.7 | 70.0 | 70.9 | 66.5 | 71.0 | 74.6 | 68.5 |
| Mean monthly sunshine hours | 157.7 | 163.3 | 206.0 | 222.2 | 276.0 | 312.1 | 337.8 | 297.9 | 239.8 | 210.0 | 138.5 | 129.2 | 2,690.4 |
| Percent possible sunshine | 53 | 55 | 56 | 56 | 61 | 69 | 73 | 70 | 64 | 61 | 47 | 45 | 60 |
| Average ultraviolet index | 1 | 2 | 4 | 6 | 8 | 9 | 9 | 8 | 6 | 4 | 2 | 1 | 5 |
| Source 1: NOAA (relative humidity and sun 1961−1990)[1][2][3] | |||||||||||||
| Source 2: Weather Atlas (UV)[4] | |||||||||||||
- ^ Mean monthly maxima and minima (i.e. the expected highest and lowest temperature readings at any point during the year or given month) calculated based on data at said location from 1991 to 2020.
- ^ Official records for Des Moines kept August 1878 to August 1939 at downtown and at Des Moines Int'l since September 1939. For more information, see Threadex
- ^ "NowData – NOAA Online Weather Data". National Oceanic and Atmospheric Administration. Retrieved June 26, 2021.
- ^ "Station: Des Moines INTP AP, IA". U.S. Climate Normals 2020: U.S. Monthly Climate Normals (1991–2020). National Oceanic and Atmospheric Administration. Retrieved June 26, 2021.
- ^ "WMO Climate Normals for DES MOINES/MUNICIPAL, IA 1961–1990". National Oceanic and Atmospheric Administration. Retrieved June 26, 2021.
- ^ "Des Moines, Iowa, USA - Monthly weather forecast and Climate data". Weather Atlas. Retrieved July 4, 2019.