| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Record high °F (°C) | 78 (26) |
85 (29) |
89 (32) |
91 (33) |
96 (36) |
109 (43) |
107 (42) |
106 (41) |
105 (41) |
99 (37) |
88 (31) |
79 (26) |
109 (43) |
| Mean maximum °F (°C) | 68.5 (20.3) |
73.3 (22.9) |
80.1 (26.7) |
85.3 (29.6) |
89.9 (32.2) |
94.7 (34.8) |
97.1 (36.2) |
96.7 (35.9) |
93.4 (34.1) |
86.4 (30.2) |
78.1 (25.6) |
69.6 (20.9) |
98.5 (36.9) |
| Mean daily maximum °F (°C) | 49.1 (9.5) |
53.8 (12.1) |
62.7 (17.1) |
72.6 (22.6) |
80.4 (26.9) |
87.7 (30.9) |
90.9 (32.7) |
90.4 (32.4) |
84.4 (29.1) |
73.5 (23.1) |
61.4 (16.3) |
52.2 (11.2) |
71.6 (22.0) |
| Daily mean °F (°C) | 39.6 (4.2) |
43.4 (6.3) |
51.5 (10.8) |
60.8 (16.0) |
69.3 (20.7) |
77.1 (25.1) |
80.7 (27.1) |
79.7 (26.5) |
73.1 (22.8) |
61.7 (16.5) |
50.3 (10.2) |
42.7 (5.9) |
60.8 (16.0) |
| Mean daily minimum °F (°C) | 30.1 (−1.1) |
33.0 (0.6) |
40.2 (4.6) |
48.9 (9.4) |
58.3 (14.6) |
66.4 (19.1) |
70.5 (21.4) |
69.0 (20.6) |
61.8 (16.6) |
49.9 (9.9) |
39.2 (4.0) |
33.3 (0.7) |
50.1 (10.1) |
| Mean minimum °F (°C) | 11.2 (−11.6) |
15.4 (−9.2) |
22.7 (−5.2) |
32.7 (0.4) |
43.1 (6.2) |
55.2 (12.9) |
62.4 (16.9) |
60.2 (15.7) |
47.3 (8.5) |
33.3 (0.7) |
23.5 (−4.7) |
17.4 (−8.1) |
9.0 (−12.8) |
| Record low °F (°C) | −17 (−27) |
−13 (−25) |
2 (−17) |
23 (−5) |
34 (1) |
42 (6) |
51 (11) |
47 (8) |
36 (2) |
26 (−3) |
−1 (−18) |
−10 (−23) |
−17 (−27) |
| Average precipitation inches (mm) | 4.02 (102) |
4.47 (114) |
4.52 (115) |
4.72 (120) |
5.02 (128) |
4.36 (111) |
4.16 (106) |
3.79 (96) |
3.80 (97) |
3.36 (85) |
3.86 (98) |
4.43 (113) |
50.51 (1,283) |
| Average snowfall inches (cm) | 2.0 (5.1) |
1.5 (3.8) |
0.7 (1.8) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.1 (0.25) |
0.4 (1.0) |
4.7 (12) |
| Average precipitation days (≥ 0.01 in) | 10.8 | 10.9 | 11.6 | 11.2 | 11.6 | 10.7 | 10.3 | 9.4 | 7.8 | 8.4 | 9.0 | 11.4 | 123.1 |
| Average snowy days (≥ 0.1 in) | 2.0 | 1.9 | 0.9 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.2 | 0.5 | 5.5 |
| Average relative humidity (%) | 70.4 | 68.5 | 64.6 | 63.2 | 69.5 | 70.4 | 72.8 | 73.1 | 73.7 | 69.4 | 70.2 | 71.4 | 69.8 |
| Average dew point °F (°C) | 26.4 (−3.1) |
29.5 (−1.4) |
36.9 (2.7) |
45.1 (7.3) |
55.9 (13.3) |
63.9 (17.7) |
68.0 (20.0) |
66.9 (19.4) |
61.2 (16.2) |
48.4 (9.1) |
39.4 (4.1) |
31.3 (−0.4) |
47.7 (8.7) |
| Mean monthly sunshine hours | 139.6 | 145.2 | 191.3 | 231.5 | 261.8 | 277.7 | 279.0 | 262.1 | 226.4 | 216.8 | 148.1 | 130.6 | 2,510.1 |
| Percent possible sunshine | 45 | 48 | 52 | 59 | 60 | 64 | 63 | 63 | 61 | 62 | 48 | 43 | 56 |
| Average ultraviolet index | 2 | 4 | 6 | 7 | 9 | 10 | 10 | 9 | 7 | 5 | 3 | 2 | 6 |
| Source 1: NOAA (relative humidity, dew point, and sun 1961−1990)[1][2][3] | |||||||||||||
| Source 2: Weather Atlas (UV index)[4] | |||||||||||||