Western Washington

Last updated on 22 May 2017

Western Washington is a region of the United States defined as that part of Washington west of the Cascade Mountains. This region is home to the state's largest city, Seattle, and the majority of the state's residents. The climate is generally far more damp and temperate than Eastern Washington.

Western Washington map.svg
Western Washington map.svg

Climate

WestWA koeppen.png
Köppen climate types in western Washington

It is known as being far wetter in climate than the eastern portion of the state, which is due in main to the effects of the Cascades rain shadow. The average place in Eastern Washington only receives an average of 46.87 centimeters (18.45 inches) of precipitation per year.[1] However, the average place in Western Washington receives an average of 167.72 centimeters (66.03 inches) of precipitation per year.[1] The average place in Western Washington gets 168 days of measurable precipitation per year.[2] The place that receives the most recorded precipitation is Lake Quinault on the Olympic Peninsula with an average of 332.92 centimeters (131.07 inches) per year.[3] The place that gets the most days of measurable precipitation is the Long Beach Experimental Station with an average of 215 days of measurable precipitation per year.[2]

Statistics for ThreadEx sites

Climate data for Olympia Regional Airport, Washington (1981–2010 normals,[a] 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)
98
(37)
104
(40)
104
(40)
98
(37)
90
(32)
74
(23)
64
(18)
104
(40)
Mean maximum °F (°C) 56.2
(13.4)
60.6
(15.9)
67.5
(19.7)
77.0
(25)
83.8
(28.8)
88.0
(31.1)
93.4
(34.1)
91.9
(33.3)
86.8
(30.4)
74.0
(23.3)
61.0
(16.1)
55.0
(12.8)
96.3
(35.7)
Average high °F (°C) 45.9
(7.7)
49.3
(9.6)
53.9
(12.2)
58.9
(14.9)
65.3
(18.5)
70.6
(21.4)
76.8
(24.9)
77.7
(25.4)
71.8
(22.1)
60.2
(15.7)
50.2
(10.1)
44.2
(6.8)
60.4
(15.8)
Average low °F (°C) 33.7
(0.9)
32.8
(0.4)
35.1
(1.7)
37.7
(3.2)
43.1
(6.2)
47.6
(8.7)
50.8
(10.4)
50.5
(10.3)
46.0
(7.8)
40.5
(4.7)
36.4
(2.4)
32.6
(0.3)
40.6
(4.8)
Mean minimum °F (°C) 18.8
(−7.3)
18.6
(−7.4)
23.8
(−4.6)
27.3
(−2.6)
32.1
(0.1)
38.2
(3.4)
42.2
(5.7)
41.1
(5.1)
35.1
(1.7)
27.3
(−2.6)
21.6
(−5.8)
16.8
(−8.4)
11.1
(−11.6)
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) 7.84
(199.1)
5.27
(133.9)
5.29
(134.4)
3.54
(89.9)
2.33
(59.2)
1.76
(44.7)
0.63
(16)
0.94
(23.9)
1.71
(43.4)
4.60
(116.8)
8.63
(219.2)
7.46
(189.5)
50
(1,270)
Average snowfall inches (cm) 1.9
(4.8)
4.7
(11.9)
0.7
(1.8)
trace 0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0.9
(2.3)
2.6
(6.6)
10.8
(27.4)
Average precipitation days (≥ 0.01 in) 20.0 15.8 18.5 15.7 12.5 9.1 4.6 4.9 7.8 14.2 20.1 19.6 162.8
Average snowy days (≥ 0.1 in) 1.1 2.2 0.3 0.2 0 0 0 0 0 0 0.5 2.0 6.3
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
Source: NOAA (relative humidity 1961–1990)[4][5][6]
Climate data for Portland, Oregon (PDX), 1981–2010 normals,[b] extremes 1940–present[c]
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °F (°C) 66
(19)
71
(22)
80
(27)
90
(32)
100
(38)
102
(39)
107
(42)
107
(42)
105
(41)
92
(33)
73
(23)
65
(18)
107
(42)
Mean maximum °F (°C) 58.4
(14.7)
61.4
(16.3)
69.5
(20.8)
78.7
(25.9)
87.1
(30.6)
91.3
(32.9)
96.7
(35.9)
96.5
(35.8)
90.6
(32.6)
78.2
(25.7)
63.6
(17.6)
57.5
(14.2)
100.2
(37.9)
Average high °F (°C) 47.0
(8.3)
51.3
(10.7)
56.7
(13.7)
61.4
(16.3)
68.0
(20)
73.5
(23.1)
80.6
(27)
81.1
(27.3)
75.8
(24.3)
63.8
(17.7)
52.8
(11.6)
45.6
(7.6)
63.1
(17.3)
Average low °F (°C) 35.8
(2.1)
36.3
(2.4)
39.6
(4.2)
43.1
(6.2)
48.6
(9.2)
53.6
(12)
57.8
(14.3)
58.0
(14.4)
53.1
(11.7)
46.0
(7.8)
40.5
(4.7)
35.2
(1.8)
45.6
(7.6)
Mean minimum °F (°C) 24.6
(−4.1)
24.5
(−4.2)
30.3
(−0.9)
34.2
(1.2)
40.1
(4.5)
46.7
(8.2)
51.2
(10.7)
50.7
(10.4)
44.4
(6.9)
35.3
(1.8)
28.4
(−2)
23.7
(−4.6)
19.6
(−6.9)
Record low °F (°C) −2
(−19)
−3
(−19)
19
(−7)
29
(−2)
29
(−2)
39
(4)
43
(6)
44
(7)
34
(1)
26
(−3)
13
(−11)
6
(−14)
−3
(−19)
Average precipitation inches (mm) 4.88
(124)
3.66
(93)
3.68
(93.5)
2.73
(69.3)
2.47
(62.7)
1.70
(43.2)
0.65
(16.5)
0.67
(17)
1.47
(37.3)
3.00
(76.2)
5.63
(143)
5.49
(139.4)
36.03
(915.2)
Average snowfall inches (cm) 0.5
(1.3)
2.1
(5.3)
0.2
(0.5)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0.2
(0.5)
1.3
(3.3)
4.3
(10.9)
Average precipitation days (≥ 0.01 in) 18.0 14.9 17.6 16.4 13.6 9.2 4.1 3.9 6.7 12.5 19.0 18.6 154.5
Average snowy days (≥ 0.1 in) 0.7 1.5 0.2 0 0 0 0 0 0 0 0.5 1.5 4.4
Average relative humidity (%) 80.9 78.0 74.6 71.6 68.7 65.8 62.8 64.8 69.4 77.9 81.5 82.7 73.2
Mean monthly sunshine hours 85.6 116.4 191.1 221.1 276.1 290.2 331.9 298.1 235.7 151.7 79.3 63.7 2,340.9
Percent possible sunshine 30 40 52 54 60 62 70 68 63 45 28 23 52
Source: NOAA (relative humidity and sun 1961–1990)[9][10][11]
Climate data for Quillayute Airport, Washington (1981–2010 normals,[d] extremes 1966–present)
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °F (°C) 69
(21)
73
(23)
73
(23)
84
(29)
92
(33)
92
(33)
97
(36)
99
(37)
97
(36)
83
(28)
69
(21)
64
(18)
99
(37)
Mean maximum °F (°C) 56.9
(13.8)
60.9
(16.1)
64.0
(17.8)
71.7
(22.1)
78.2
(25.7)
81.1
(27.3)
84.9
(29.4)
85.7
(29.8)
82.0
(27.8)
72.0
(22.2)
59.5
(15.3)
55.3
(12.9)
90.7
(32.6)
Average high °F (°C) 47.1
(8.4)
49.1
(9.5)
51.4
(10.8)
54.8
(12.7)
59.5
(15.3)
63.1
(17.3)
67.4
(19.7)
68.6
(20.3)
66.2
(19)
58.2
(14.6)
50.3
(10.2)
46.0
(7.8)
56.8
(13.8)
Average low °F (°C) 36.0
(2.2)
35.2
(1.8)
36.8
(2.7)
38.6
(3.7)
43.1
(6.2)
47.5
(8.6)
50.5
(10.3)
50.5
(10.3)
46.9
(8.3)
41.8
(5.4)
38.1
(3.4)
34.7
(1.5)
41.6
(5.3)
Mean minimum °F (°C) 23.1
(−4.9)
22.7
(−5.2)
26.7
(−2.9)
28.9
(−1.7)
33.4
(0.8)
38.8
(3.8)
41.7
(5.4)
42.0
(5.6)
36.4
(2.4)
30.1
(−1.1)
25.7
(−3.5)
21.9
(−5.6)
17.9
(−7.8)
Record low °F (°C) 7
(−14)
11
(−12)
19
(−7)
23
(−5)
29
(−2)
33
(1)
38
(3)
36
(2)
28
(−2)
23
(−5)
5
(−15)
7
(−14)
5
(−15)
Average precipitation inches (mm) 14.61
(371.1)
10.35
(262.9)
10.83
(275.1)
7.85
(199.4)
5.11
(129.8)
3.50
(88.9)
1.98
(50.3)
2.49
(63.2)
3.82
(97)
10.49
(266.4)
15.52
(394.2)
12.99
(329.9)
99.54
(2,528.3)
Average snowfall inches (cm) 2.0
(5.1)
2.6
(6.6)
0.7
(1.8)
0.1
(0.3)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
1.4
(3.6)
2.1
(5.3)
8.9
(22.6)
Average precipitation days (≥ 0.01 in) 22.8 18.4 21.9 19.0 16.7 14.4 10.3 8.9 10.9 18.1 22.8 22.1 206.3
Average snowy days (≥ 0.1 in) 1.7 1.9 0.8 0.4 0 0 0 0 0 0 0.9 1.3 7.0
Average relative humidity (%) 88.5 86.4 84.4 81.2 80.3 80.3 79.9 82.3 82.5 87.0 88.9 90.0 84.3
Mean monthly sunshine hours 55.4 80.3 115.0 147.4 170.6 167.8 209.7 194.8 173.2 112.7 55.3 48.1 1,530.3
Percent possible sunshine 20 28 31 36 36 35 43 44 46 34 20 18 34
Source: NOAA (relative humidity 1966–1990, sun 1967–1990)[9][10][11]
Climate data for Seattle (SeaTac Airport), 1981–2010 normals,[e] extremes 1894–present[f]
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °F (°C) 67
(19)
70
(21)
78
(26)
89
(32)
93
(34)
98
(37)
103
(39)
99
(37)
98
(37)
89
(32)
74
(23)
66
(19)
103
(39)
Mean maximum °F (°C) 56.4
(13.6)
60.3
(15.7)
66.0
(18.9)
74.7
(23.7)
81.5
(27.5)
85.5
(29.7)
90.6
(32.6)
88.8
(31.6)
84.6
(29.2)
72.2
(22.3)
60.7
(15.9)
55.9
(13.3)
93.8
(34.3)
Average high °F (°C) 47.2
(8.4)
49.9
(9.9)
53.7
(12.1)
58.5
(14.7)
64.7
(18.2)
69.9
(21.1)
75.8
(24.3)
76.3
(24.6)
70.5
(21.4)
59.7
(15.4)
50.9
(10.5)
45.7
(7.6)
60.3
(15.7)
Daily mean °F (°C) 42.0
(5.6)
43.4
(6.3)
46.5
(8.1)
50.3
(10.2)
56.0
(13.3)
60.9
(16.1)
65.7
(18.7)
66.1
(18.9)
61.3
(16.3)
52.8
(11.6)
45.4
(7.4)
40.6
(4.8)
52.6
(11.4)
Average low °F (°C) 36.9
(2.7)
36.9
(2.7)
39.3
(4.1)
42.2
(5.7)
47.3
(8.5)
51.9
(11.1)
55.6
(13.1)
55.9
(13.3)
52.1
(11.2)
45.8
(7.7)
40.0
(4.4)
35.6
(2)
45.0
(7.2)
Mean minimum °F (°C) 25.4
(−3.7)
25.9
(−3.4)
31.3
(−0.4)
35.0
(1.7)
39.7
(4.3)
46.2
(7.9)
50.6
(10.3)
50.7
(10.4)
44.6
(7)
35.7
(2.1)
28.7
(−1.8)
24.0
(−4.4)
19.5
(−6.9)
Record low °F (°C) 0
(−18)
1
(−17)
11
(−12)
29
(−2)
28
(−2)
38
(3)
43
(6)
44
(7)
35
(2)
28
(−2)
6
(−14)
6
(−14)
0
(−18)
Average precipitation inches (mm) 5.57
(141.5)
3.50
(88.9)
3.72
(94.5)
2.71
(68.8)
1.94
(49.3)
1.57
(39.9)
0.70
(17.8)
0.88
(22.4)
1.50
(38.1)
3.48
(88.4)
6.57
(166.9)
5.35
(135.9)
37.49
(952.2)
Average snowfall inches (cm) 1.4
(3.6)
1.7
(4.3)
0.8
(2)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
1.2
(3)
1.7
(4.3)
6.8
(17.3)
Average precipitation days (≥ 0.01 in) 18.2 14.7 16.9 14.3 12.0 9.1 5.0 4.8 7.9 13.1 18.4 17.6 152.0
Average snowy days (≥ 0.1 in) 1.3 0.9 0.5 0 0 0 0 0 0 0 0.3 1.6 4.6
Average relative humidity (%) 78.0 75.2 73.6 71.4 68.9 67.1 65.4 68.2 73.2 78.6 79.8 80.1 73.3
Mean monthly sunshine hours 69.8 108.8 178.4 207.3 253.7 268.4 312.0 281.4 221.7 142.6 72.7 52.9 2,169.7
Percent possible sunshine 25 38 48 51 54 56 65 64 59 42 26 20 49
Source: NOAA (relative humidity and sun 1961–1990)[9][13][11]

Population

In the 2010 census, Western Washington had a population of 5,229,486[14] out of the 6,724,540 in the entire state of Washington.[15] This makes the population comparable to that of Minnesota with a population of 5,303,925.[15] It has a land area of 24,742 square miles (64,080 km2), for a population density of 211.36 people per square mile (81.61 people per square kilometer).

Counties

Counties in Western Washington:

Cities of note

Major cities in Western Washington:[16]

Notes

  1. ^ Mean monthly maxima and minima (i.e. the highest and lowest temperature readings during an entire month or year) calculated based on data at said location from 1981 to 2010.
  2. ^ Mean monthly maxima and minima (i.e. the highest and lowest temperature readings during an entire month or year) calculated based on data at said location from 1981 to 2010.
  3. ^ Official records for Portland have been kept at PDX since 13 October 1940.[7] In January 1996, snow measurements for PDX were moved to the NWS Portland office 4 mi (6.4 km) to the east at 5241 NE 122nd Avenue, Portland, OR 97230-1089.[8]
  4. ^ Mean monthly maxima and minima (i.e. the highest and lowest temperature readings during an entire month or year) calculated based on data at said location from 1981 to 2010.
  5. ^ Mean monthly maxima and minima (i.e. the highest and lowest temperature readings during an entire month or year) calculated based on data at said location from 1981 to 2010.
  6. ^ Official records are restricted to SeaTac Airport from January 1945 onward.[12]

References

  1. ^ a b http://www.wrcc.dri.edu/summary/Climsmwa.html Western Regional Climate Data Center Website
  2. ^ a b http://www.wrcc.dri.edu/htmlfiles/wa/wa.01.html Western Regional Climate Data Center, Days of Precipitation
  3. ^ "QUINAULT RS, WASHINGTON - Climate Summary". dri.edu. Retrieved 20 June 2015.
  4. ^ "NOWData - NOAA Online Weather Data". National Oceanic and Atmospheric Administration. Retrieved 2016-09-05.
  5. ^ "Station Name: WA OLYMPIA AP". National Oceanic and Atmospheric Administration. Retrieved 2016-09-05.
  6. ^ "WMO Climate Normals for OLYMPIA, WA 1961–1990". National Oceanic and Atmospheric Administration. Retrieved 2016-09-05.
  7. ^ ThreadEx
  8. ^ "AIRPORT Portland: Monthly and Seasonal Snowfall (inches)" (PDF). NWS Portland, OR. Retrieved 2014-06-22.
  9. ^ a b c "NowData – NOAA Online Weather Data". National Oceanic and Atmospheric Administration. Retrieved 2016-04-11. Cite error: Invalid <ref> tag; name "NOWData" defined multiple times with different content (see the help page). Cite error: Invalid <ref> tag; name "NOWData" defined multiple times with different content (see the help page).
  10. ^ a b "Station Name: OR PORTLAND INTL AP". National Oceanic and Atmospheric Administration. Retrieved 2014-03-13. Cite error: Invalid <ref> tag; name "NOAA_txt" defined multiple times with different content (see the help page).
  11. ^ a b c "WMO Climate Normals for PORTLAND OR 1961–1990". National Oceanic and Atmospheric Administration. Retrieved 2014-03-10. Cite error: Invalid <ref> tag; name "NOAAsun" defined multiple times with different content (see the help page). Cite error: Invalid <ref> tag; name "NOAAsun" defined multiple times with different content (see the help page).
  12. ^ "National Weather Service - NWS Seattle". NWS Seattle, WA. Retrieved 2015-10-25.
  13. ^ "Station Name: WA SEATTLE TACOMA INTL AP". National Oceanic and Atmospheric Administration. Retrieved 2016-09-05.
  14. ^ "Washington population by county - Census 2010: Washington - The Spokesman-Review". spokesman.com. Retrieved 20 June 2015.
  15. ^ a b See List of U.S. states and territories by population for the most recent state population figures.
  16. ^ US Census Bureau for Washington

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