 |
|
Map of Washington displaying topographic relief
|
 |
| http://docweather.com/4/show/197/ Map displaying the Aluecian Low and the North Pacific High and the direction of the winds. |
Yakima
receives little annual precipitation compared to cities on the western slope of
the Cascades. Warm moist air from the
North Pacific High and the California current make landfall on the west coast.
The Cascades promote orographic lifting for the air masses traveling onshore.
As the air masses rise they cool and reach the dew point. Once they reach the
dew point precipitation begins. By the time the air masses make it over the mountains,
they have dumped their moisture. The air masses warm according to the dry
adiabatic lapse rate and carry warm air to the eastern plains of Washington.
That is why Yakima has generally warm dry weather. Yakima receives only 8
inches of precipitation annually while the western slope receives anywhere from
90 to 180 inches.
 |
|
Annual precipitation for the state of Washington. Notice the high precipitation on the western slope and the low precipitation on the eastern slope and Yakima Valley.
|
The
rain/snow season is December through March averaging at least one inch per
month of precipitation. The city receives quite a lot of sunshine with 109
clear days annually with relatively low humidity. This allows for long wave
radiation to enter and warm the surface during the day and escape at night. The
arid region also allows for large gap in diurnal temperatures ranging 20 to 30
degrees Fahrenheit depending on the weather.
Yakima Temperature
|
Jan
|
Feb
|
Mar
|
Apr
|
May
|
Jun
|
Jul
|
Aug
|
Sep
|
Oct
|
Nov
|
Dec
|
Annual
|
|
Avg. Temperature
|
29.7
|
36.4
|
43.0
|
49.4
|
57.0
|
64.6
|
69.9
|
69.0
|
60.7
|
49.9
|
38.6
|
29.8
|
49.8
|
|
Avg. Max Temperature
|
37.5
|
46.4
|
55.2
|
63.2
|
71.6
|
79.9
|
86.7
|
85.7
|
76.8
|
64.4
|
48.3
|
37.5
|
62.8
|
|
Avg. Min Temperature
|
21.8
|
26.4
|
30.8
|
35.5
|
42.3
|
49.2
|
53.1
|
52.3
|
44.6
|
35.3
|
29.0
|
22.1
|
36.9
|
|
Days with Max Temp
of 90 F or Higher
|
0.0
|
0.0
|
0.0
|
< 0.5
|
1.0
|
4.0
|
14.0
|
11.0
|
2.0
|
0.0
|
0.0
|
0.0
|
32.0
|
|
Days with Min Temp
Below Freezing
|
28.0
|
24.0
|
20.0
|
12.0
|
3.0
|
< 0.5
|
0.0
|
0.0
|
1.0
|
11.0
|
22.0
|
28.0
|
148
|
|
Yakima Heating and
Cooling
|
Jan
|
Feb
|
Mar
|
Apr
|
May
|
Jun
|
Jul
|
Aug
|
Sep
|
Oct
|
Nov
|
Dec
|
Annual
|
|
Heating Degree Days
|
1094
|
801
|
682
|
468
|
255
|
90.0
|
19.0
|
38.0
|
169
|
468
|
792
|
1091
|
5967
|
|
Cooling Degree Days
|
0.0
|
0.0
|
0.0
|
0.0
|
7.0
|
78.0
|
171
|
162
|
40.0
|
0.0
|
0.0
|
0.0
|
458
|
|
Yakima Precipitation
|
Jan
|
Feb
|
Mar
|
Apr
|
May
|
Jun
|
Jul
|
Aug
|
Sep
|
Oct
|
Nov
|
Dec
|
Annual
|
|
Precipitation
(inches)
|
1.2
|
0.7
|
0.7
|
0.5
|
0.5
|
0.5
|
0.2
|
0.4
|
0.4
|
0.5
|
1.0
|
1.4
|
8.0
|
|
Days with
Precipitation 0.01 inch or More
|
10.0
|
7.0
|
7.0
|
5.0
|
5.0
|
5.0
|
2.0
|
3.0
|
3.0
|
5.0
|
9.0
|
10.0
|
70.0
|
|
Monthly Snowfall
(inches)
|
8.3
|
3.4
|
1.5
|
0.0
|
< 0.05
|
0.0
|
0.0
|
0.0
|
0.0
|
0.1
|
2.6
|
8.7
|
24.6
|
|
Other Yakima Weather
Indicators
|
Jan
|
Feb
|
Mar
|
Apr
|
May
|
Jun
|
Jul
|
Aug
|
Sep
|
Oct
|
Nov
|
Dec
|
Annual
|
|
Average Wind Speed
|
5.6
|
6.4
|
7.9
|
8.6
|
8.5
|
8.2
|
7.8
|
7.4
|
7.3
|
6.6
|
5.8
|
5.1
|
7.1
|
|
Clear Days
|
4.0
|
4.0
|
6.0
|
6.0
|
8.0
|
10.0
|
19.0
|
18.0
|
15.0
|
9.0
|
5.0
|
4.0
|
109
|
|
Partly Cloudy Days
|
5.0
|
6.0
|
8.0
|
9.0
|
11.0
|
10.0
|
8.0
|
8.0
|
8.0
|
8.0
|
6.0
|
5.0
|
92.0
|
|
Cloudy Days
|
22.0
|
18.0
|
17.0
|
14.0
|
12.0
|
10.0
|
4.0
|
6.0
|
7.0
|
13.0
|
19.0
|
22.0
|
164
|
|
Avg. Relative
Humidity
|
66.0
|
76.5
|
67.5
|
57.0
|
52.5
|
50.5
|
49.5
|
48.5
|
52.0
|
56.0
|
63.5
|
74.0
|
76.0
|
On cloudy
days, beautiful cumulus clouds can be seen traveling across the valley. Though
few produce rain until they build up and start to rise on the Rocky Mountains,
far from the Yakima Valley.
 |
| http://www.destination360.com/north-america/us/washington/yakima Beautiful cumulus clouds shading the Yakima Valley. Notice the flat bottoms of the clouds indicating the elevation of the dew point. |
