Climate data for St. Louis, Missouri ( Lambert–St. Louis Int'l), 1991−2020 normals, [a] extremes 1874−present [b] | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
Record high °F (°C) | 77 (25) |
85 (29) |
92 (33) |
93 (34) |
98 (37) |
108 (42) |
115 (46) |
110 (43) |
104 (40) |
94 (34) |
86 (30) |
76 (24) |
115 (46) |
Mean maximum °F (°C) | 64.7 (18.2) |
71.0 (21.7) |
79.4 (26.3) |
86.4 (30.2) |
90.4 (32.4) |
95.5 (35.3) |
99.2 (37.3) |
99.1 (37.3) |
93.4 (34.1) |
87.0 (30.6) |
75.5 (24.2) |
66.9 (19.4) |
100.7 (38.2) |
Mean daily maximum °F (°C) | 40.4 (4.7) |
45.8 (7.7) |
56.6 (13.7) |
68.0 (20.0) |
77.1 (25.1) |
85.9 (29.9) |
89.6 (32.0) |
88.3 (31.3) |
81.1 (27.3) |
69.2 (20.7) |
55.5 (13.1) |
44.5 (6.9) |
66.8 (19.3) |
Daily mean °F (°C) | 32.1 (0.1) |
36.7 (2.6) |
46.6 (8.1) |
57.5 (14.2) |
67.5 (19.7) |
76.5 (24.7) |
80.4 (26.9) |
78.8 (26.0) |
71.0 (21.7) |
59.1 (15.1) |
46.5 (8.1) |
36.5 (2.5) |
57.4 (14.1) |
Mean daily minimum °F (°C) | 23.8 (−4.6) |
27.6 (−2.4) |
36.7 (2.6) |
47.0 (8.3) |
57.9 (14.4) |
67.2 (19.6) |
71.1 (21.7) |
69.3 (20.7) |
60.9 (16.1) |
49.1 (9.5) |
37.4 (3.0) |
28.5 (−1.9) |
48.0 (8.9) |
Mean minimum °F (°C) | 4.4 (−15.3) |
9.6 (−12.4) |
17.8 (−7.9) |
32.2 (0.1) |
43.5 (6.4) |
55.5 (13.1) |
61.4 (16.3) |
60.1 (15.6) |
47.1 (8.4) |
33.6 (0.9) |
22.0 (−5.6) |
11.0 (−11.7) |
1.2 (−17.1) |
Record low °F (°C) | −22 (−30) |
−18 (−28) |
−5 (−21) |
20 (−7) |
31 (−1) |
43 (6) |
51 (11) |
47 (8) |
32 (0) |
21 (−6) |
1 (−17) |
−16 (−27) |
−22 (−30) |
Average precipitation inches (mm) | 2.59 (66) |
2.23 (57) |
3.50 (89) |
4.73 (120) |
4.82 (122) |
4.49 (114) |
3.93 (100) |
3.38 (86) |
2.96 (75) |
3.15 (80) |
3.42 (87) |
2.50 (64) |
41.70 (1,059) |
Average snowfall inches (cm) | 5.7 (14) |
4.3 (11) |
2.3 (5.8) |
0.2 (0.51) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.9 (2.3) |
3.2 (8.1) |
16.6 (42) |
Average precipitation days (≥ 0.01 in) | 9.3 | 8.7 | 10.8 | 11.5 | 12.6 | 9.8 | 8.9 | 8.4 | 7.3 | 8.5 | 9.0 | 9.0 | 113.8 |
Average snowy days (≥ 0.1 in) | 4.7 | 3.9 | 1.7 | 0.2 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.8 | 3.2 | 14.5 |
Average relative humidity (%) | 73.0 | 72.0 | 68.3 | 63.5 | 66.5 | 67.1 | 68.0 | 70.0 | 71.6 | 68.7 | 72.2 | 75.8 | 69.7 |
Average dew point °F (°C) | 20.1 (−6.6) |
24.1 (−4.4) |
33.1 (0.6) |
42.3 (5.7) |
52.9 (11.6) |
62.1 (16.7) |
66.6 (19.2) |
65.1 (18.4) |
58.6 (14.8) |
46.0 (7.8) |
36.0 (2.2) |
25.5 (−3.6) |
44.4 (6.9) |
Mean monthly sunshine hours | 161.2 | 158.3 | 198.3 | 223.5 | 266.5 | 291.9 | 308.9 | 269.8 | 236.1 | 208.4 | 140.9 | 129.9 | 2,593.7 |
Percent possible sunshine | 53 | 53 | 53 | 56 | 60 | 66 | 68 | 64 | 63 | 60 | 47 | 44 | 58 |
Average ultraviolet index | 1.7 | 2.7 | 4.5 | 6.4 | 7.9 | 9.0 | 9.1 | 8.2 | 6.3 | 4.0 | 2.3 | 1.6 | 5.3 |
Source 1: NOAA (relative humidity, dew point, and sun 1961−1990) [2] [3] [4] | |||||||||||||
Source 2: UV Index Today (1995 to 2022) [5] |