| Climate data for Olympia Regional Airport, Washington (1991−2020 normals, extremes 1948−present) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °F (°C) | 64 (18) |
73 (23) |
79 (26) |
88 (31) |
96 (36) |
110 (43) |
104 (40) |
104 (40) |
98 (37) |
90 (32) |
74 (23) |
64 (18) |
110 (43) |
| Mean maximum °F (°C) | 56.3 (13.5) |
59.4 (15.2) |
67.9 (19.9) |
76.2 (24.6) |
83.9 (28.8) |
87.9 (31.1) |
93.6 (34.2) |
92.2 (33.4) |
86.3 (30.2) |
73.7 (23.2) |
61.5 (16.4) |
55.5 (13.1) |
96.0 (35.6) |
| Mean daily maximum °F (°C) | 46.0 (7.8) |
49.1 (9.5) |
53.7 (12.1) |
58.9 (14.9) |
66.1 (18.9) |
70.8 (21.6) |
77.6 (25.3) |
78.0 (25.6) |
72.1 (22.3) |
60.2 (15.7) |
50.6 (10.3) |
44.9 (7.2) |
60.7 (15.9) |
| Daily mean °F (°C) | 39.6 (4.2) |
40.7 (4.8) |
44.1 (6.7) |
48.2 (9.0) |
54.5 (12.5) |
59.1 (15.1) |
64.2 (17.9) |
64.2 (17.9) |
59.1 (15.1) |
50.3 (10.2) |
43.2 (6.2) |
38.9 (3.8) |
50.5 (10.3) |
| Mean daily minimum °F (°C) | 33.2 (0.7) |
32.3 (0.2) |
34.5 (1.4) |
37.5 (3.1) |
43.0 (6.1) |
47.4 (8.6) |
50.7 (10.4) |
50.5 (10.3) |
46.2 (7.9) |
40.5 (4.7) |
35.8 (2.1) |
32.8 (0.4) |
40.4 (4.7) |
| Mean minimum °F (°C) | 18.8 (−7.3) |
19.0 (−7.2) |
23.9 (−4.5) |
27.5 (−2.5) |
32.3 (0.2) |
38.4 (3.6) |
42.7 (5.9) |
41.9 (5.5) |
35.9 (2.2) |
27.9 (−2.3) |
21.6 (−5.8) |
18.4 (−7.6) |
12.6 (−10.8) |
| Record low °F (°C) | −8 (−22) |
−1 (−18) |
9 (−13) |
23 (−5) |
25 (−4) |
30 (−1) |
35 (2) |
33 (1) |
25 (−4) |
14 (−10) |
−1 (−18) |
−7 (−22) |
−8 (−22) |
| Average precipitation inches (mm) | 7.80 (198) |
5.09 (129) |
5.68 (144) |
3.67 (93) |
2.26 (57) |
1.46 (37) |
0.53 (13) |
0.96 (24) |
2.04 (52) |
5.07 (129) |
8.21 (209) |
7.85 (199) |
50.62 (1,286) |
| Average snowfall inches (cm) | 2.0 (5.1) |
0.6 (1.5) |
0.1 (0.25) |
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) |
0.0 (0.0) |
1.2 (3.0) |
3.9 (9.9) |
| Average precipitation days (≥ 0.01 in) | 20.3 | 16.4 | 18.8 | 16.3 | 11.4 | 8.5 | 4.0 | 4.8 | 8.1 | 15.1 | 19.5 | 20.2 | 163.4 |
| Average snowy days (≥ 0.1 in) | 0.5 | 0.7 | 0.1 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.1 | 0.8 | 2.2 |
| Average relative humidity (%) | 87.5 | 84.5 | 80.0 | 75.6 | 72.9 | 72.4 | 70.8 | 72.1 | 77.6 | 85.1 | 88.4 | 89.1 | 79.7 |
| Average dew point °F (°C) | 34.5 (1.4) |
36.0 (2.2) |
36.9 (2.7) |
39.2 (4.0) |
43.9 (6.6) |
48.9 (9.4) |
52.0 (11.1) |
52.7 (11.5) |
49.6 (9.8) |
44.8 (7.1) |
39.6 (4.2) |
35.4 (1.9) |
42.8 (6.0) |
| Source 1: NOAA (dew points and relative humidity 1961–1990)[1][2] | |||||||||||||
| Source 2: National Weather Service[3] | |||||||||||||
- ^ "U.S. Climate Normals Quick Access". National Oceanic and Atmospheric Administration. Archived from the original on 2023-07-05. Retrieved September 14, 2022.
- ^ "WMO Climate Normals for OLYMPIA, WA 1961–1990". National Oceanic and Atmospheric Administration. Archived from the original on 2023-07-05. Retrieved July 5, 2023.
- ^ "NowData - NOAA Online Weather Data". National Oceanic and Atmospheric Administration. Retrieved June 27, 2021.