PIPER—FLORA OF THE STATE OF WASHINGTON. 31 
As regards temperature then the climate of this region is remark- 
ably equable, without marked extremes in either summer or winter. 
The region in immediate proximity to the ocean has the coolest sum- 
mer, and the extreme winter temperatures have never reached zero. 
EASTERN WASHINGTON. 
The records of the United States Weather Bureau concern nearly 
forty different stations in eastern Washington for periods of from 
one to twenty-three years. Fifteen of these stations he within the 
Upper Sonoran area, the remainder within the Arid Transition. The 
Upper Sonoran stations are Ellensburg, Ephrata, Kennewick, Lind, 
Mottinger’s Ranch, Moxee, Odessa, South Ellensburg, Sunnyside, 
Trinidad, Walla Walla, Wenache, and Zindel. The normal annual 
mean temperature for the whole region is 48.7°; for the Arid Transi- 
tion stations alone it is 45.9°; and for the Upper Sonoran stations it 
is 51.3°. | . 
The normal monthly mean temperatures for the stations located in 
the Arid Transition are as follows: 
Temperature data for Arid Transition area. 
Month. | Degrees F. Month. Degrees F. 
January_-----_----------- 21to034 = July____--____--_-------- 62 to 72 
February _______ -- aa aHe. 25 to 38 | August____--_-----------. 62 to 74 
March_______------------ 30 to 43 ~September___-_---_--_---- 51 to 63 
April________------------ | 43 to 52 | October____-- ~a---------- 44 to 55 
May---_----- ------------ | 51to58 | November____-------_---- 32 to 42 
June__________--_------_. | 55 to 65 || December_____-_-_-_-__----- 25 to 36 
The highest temperature recorded at these stations is 105°, the 
lowest is —32°. | 
The corresponding data for the stations located in the Upper 
Sonoran area are as follows: 
Temperature data for Upper Sonoran area. 
Month. | Degrees F. | Month. Degrees F. 
I 
| 
January_—~---------------| 25 to 87 |) July__-------_--------- — 65 to 77 
February _______-------+-. 25 to 39 | August_______-___--_--_-_-. 66 to 75 
March____-________--_--- | 39 to 49 || September____---_-_ _-____. 56 to 64 
April_______--_-________- | 48 to55 || October___-__--_----__-_- 36 to 43 
May____-_--------_--_--- | 55 to 63 | November__--------__-__- 28 to 38 
June__________-_~-_~-_--_-. 59 to 71 | December____------------- 47 to 57 
The maximum temperature ever observed at any of the above 
stations is 113°; the minimum is —30°. 
