| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Record high °F (°C) | 80 (27) | 84 (29) | 93 (34) | 95 (35) | 99 (37) | 104 (40) | 106 (41) | 106 (41) | 104 (40) | 98 (37) | 86 (30) | 79 (26) | 106 (41) |
| Mean maximum °F (°C) | 66.7 (19.3) | 68.1 (20.1) | 77.3 (25.2) | 86.4 (30.2) | 91.0 (32.8) | 95.7 (35.4) | 98.1 (36.7) | 96.5 (35.8) | 91.9 (33.3) | 84.5 (29.2) | 74.8 (23.8) | 67.1 (19.5) | 99.1 (37.3) |
| Mean daily maximum °F (°C) | 44.8 (7.1) | 48.3 (9.1) | 56.5 (13.6) | 68.0 (20.0) | 76.5 (24.7) | 85.1 (29.5) | 89.6 (32.0) | 87.8 (31.0) | 80.7 (27.1) | 69.4 (20.8) | 58.2 (14.6) | 48.8 (9.3) | 67.8 (19.9) |
| Daily mean °F (°C) | 37.5 (3.1) | 40.0 (4.4) | 47.6 (8.7) | 58.2 (14.6) | 67.2 (19.6) | 76.3 (24.6) | 81.0 (27.2) | 79.4 (26.3) | 72.4 (22.4) | 60.8 (16.0) | 49.9 (9.9) | 41.7 (5.4) | 59.3 (15.2) |
| Mean daily minimum °F (°C) | 30.1 (−1.1) | 31.8 (−0.1) | 38.6 (3.7) | 48.4 (9.1) | 58.0 (14.4) | 67.5 (19.7) | 72.4 (22.4) | 71.0 (21.7) | 64.1 (17.8) | 52.2 (11.2) | 41.6 (5.3) | 34.5 (1.4) | 50.9 (10.5) |
| Mean minimum °F (°C) | 14.3 (−9.8) | 16.9 (−8.4) | 23.4 (−4.8) | 34.9 (1.6) | 45.5 (7.5) | 55.7 (13.2) | 63.8 (17.7) | 62.1 (16.7) | 51.3 (10.7) | 38.7 (3.7) | 28.8 (−1.8) | 21.3 (−5.9) | 12.3 (−10.9) |
| Record low °F (°C) | −14 (−26) | −15 (−26) | 4 (−16) | 15 (−9) | 33 (1) | 43 (6) | 52 (11) | 49 (9) | 36 (2) | 26 (−3) | 11 (−12) | −13 (−25) | −15 (−26) |
| Average precipitation inches (mm) | 2.86 (73) | 2.62 (67) | 3.50 (89) | 3.21 (82) | 3.94 (100) | 4.20 (107) | 4.33 (110) | 3.25 (83) | 3.93 (100) | 3.66 (93) | 2.91 (74) | 3.41 (87) | 41.82 (1,062) |
| Average snowfall inches (cm) | 4.9 (12) | 5.0 (13) | 2.0 (5.1) | 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) | 1.7 (4.3) | 13.7 (35) |
| Average precipitation days (≥ 0.01 in) | 9.7 | 9.3 | 11.0 | 10.8 | 11.6 | 10.6 | 10.5 | 8.7 | 8.7 | 8.3 | 8.4 | 10.1 | 117.7 |
| Average snowy days (≥ 0.1 in) | 2.8 | 2.7 | 1.1 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.1 | 1.3 | 8.0 |
| Average relative humidity (%) | 62.1 | 60.5 | 58.6 | 58.0 | 64.5 | 65.8 | 66.9 | 69.3 | 69.7 | 67.4 | 64.7 | 64.1 | 64.3 |
| Average dew point °F (°C) | 21.7 (−5.7) | 23.5 (−4.7) | 31.3 (−0.4) | 39.7 (4.3) | 52.3 (11.3) | 61.5 (16.4) | 66.0 (18.9) | 65.8 (18.8) | 59.5 (15.3) | 47.5 (8.6) | 37.0 (2.8) | 27.1 (−2.7) | 44.4 (6.9) |
| Mean monthly sunshine hours | 144.6 | 151.8 | 204.0 | 228.2 | 260.5 | 283.2 | 280.5 | 263.1 | 225.0 | 203.6 | 150.2 | 133.0 | 2,527.7 |
| Percent possible sunshine | 48 | 50 | 55 | 57 | 59 | 64 | 62 | 62 | 60 | 59 | 50 | 45 | 57 |
| Average ultraviolet index | 2 | 3 | 5 | 7 | 8 | 9 | 9 | 8 | 7 | 4 | 3 | 2 | 6 |
| Source 1: NOAA (relative humidity, dew point and sun 1961−1990) | |||||||||||||
| Source 2: Weather Atlas (UV) | |||||||||||||
