| Climate data for Sioux City, Iowa (Sioux Gateway Airport), 1991–2020 normals, extremes 1889–present | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °F (°C) | 71 (22) |
75 (24) |
91 (33) |
98 (37) |
106 (41) |
108 (42) |
111 (44) |
108 (42) |
103 (39) |
96 (36) |
82 (28) |
71 (22) |
111 (44) |
| Mean maximum °F (°C) | 52.2 (11.2) |
57.9 (14.4) |
74.7 (23.7) |
85.7 (29.8) |
92.5 (33.6) |
95.4 (35.2) |
95.3 (35.2) |
94.1 (34.5) |
91.6 (33.1) |
85.3 (29.6) |
70.3 (21.3) |
54.4 (12.4) |
98.3 (36.8) |
| Mean daily maximum °F (°C) | 29.5 (−1.4) |
34.2 (1.2) |
47.6 (8.7) |
61.1 (16.2) |
72.3 (22.4) |
81.9 (27.7) |
85.0 (29.4) |
82.6 (28.1) |
76.6 (24.8) |
62.8 (17.1) |
46.8 (8.2) |
33.4 (0.8) |
59.5 (15.3) |
| Daily mean °F (°C) | 20.0 (−6.7) |
24.5 (−4.2) |
36.7 (2.6) |
48.9 (9.4) |
60.5 (15.8) |
70.7 (21.5) |
74.2 (23.4) |
71.7 (22.1) |
63.9 (17.7) |
50.3 (10.2) |
35.9 (2.2) |
24.1 (−4.4) |
48.4 (9.1) |
| Mean daily minimum °F (°C) | 10.4 (−12.0) |
14.8 (−9.6) |
25.9 (−3.4) |
36.7 (2.6) |
48.7 (9.3) |
59.4 (15.2) |
63.4 (17.4) |
60.8 (16.0) |
51.2 (10.7) |
37.9 (3.3) |
25.0 (−3.9) |
14.8 (−9.6) |
37.4 (3.0) |
| Mean minimum °F (°C) | −12.1 (−24.5) |
−6.8 (−21.6) |
4.1 (−15.5) |
20.0 (−6.7) |
33.4 (0.8) |
46.3 (7.9) |
51.2 (10.7) |
49.2 (9.6) |
34.3 (1.3) |
20.2 (−6.6) |
7.0 (−13.9) |
−6.9 (−21.6) |
−16.1 (−26.7) |
| Record low °F (°C) | −35 (−37) |
−31 (−35) |
−22 (−30) |
−2 (−19) |
23 (−5) |
38 (3) |
41 (5) |
37 (3) |
24 (−4) |
5 (−15) |
−9 (−23) |
−28 (−33) |
−35 (−37) |
| Average precipitation inches (mm) | 0.69 (18) |
0.86 (22) |
1.76 (45) |
3.15 (80) |
3.87 (98) |
4.35 (110) |
3.35 (85) |
3.94 (100) |
2.84 (72) |
2.20 (56) |
1.27 (32) |
0.99 (25) |
29.27 (743) |
| Average snowfall inches (cm) | 7.7 (20) |
8.7 (22) |
5.7 (14) |
2.3 (5.8) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.8 (2.0) |
3.2 (8.1) |
7.6 (19) |
36.0 (91) |
| Average precipitation days (≥ 0.01 in) | 6.8 | 6.5 | 8.1 | 10.0 | 12.0 | 11.7 | 9.0 | 9.8 | 8.0 | 7.6 | 5.9 | 6.8 | 102.2 |
| Average snowy days (≥ 0.1 in) | 5.9 | 5.7 | 3.4 | 1.4 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.5 | 2.5 | 5.4 | 24.8 |
| Average relative humidity (%) | 72.2 | 72.4 | 69.7 | 61.6 | 62.3 | 65.5 | 69.2 | 72.0 | 70.8 | 66.2 | 72.3 | 75.9 | 69.2 |
| Mean monthly sunshine hours | 171.1 | 165.5 | 211.9 | 232.3 | 271.8 | 310.2 | 330.9 | 292.9 | 235.5 | 209.3 | 146.4 | 138.3 | 2,716.1 |
| Percent possible sunshine | 58 | 56 | 57 | 58 | 60 | 68 | 71 | 68 | 63 | 61 | 50 | 49 | 61 |
| Source: NOAA (relative humidity and sun 1961–1990)[1][2][3] | |||||||||||||
- ^ "NowData – NOAA Online Weather Data". National Oceanic and Atmospheric Administration. Retrieved June 27, 2021.
- ^ "Station: Sioux City Gateway AP, IA". U.S. Climate Normals 2020: U.S. Monthly Climate Normals (1991–2020). National Oceanic and Atmospheric Administration. Retrieved June 27, 2021.
- ^ "WMO Climate Normals for SIOUX CITY/MUNICIPAL, IA 1961–1990". National Oceanic and Atmospheric Administration. Retrieved June 27, 2021.