deschutes county climate
Introduction

Deschutes County lies in the central part of Oregon along the eastern side of the Cascades. It is within two different climate divisions, Climate Division 5 (High Plateau) and Climate Division 7 (South Central Oregon) established by the National Climatic Data Center. Below is a description of the climate of Division 5 and 7 followed by specific descriptions of Deschutes County. Climate tables for various parameters, as observed at long-term climate stations in Deschutes County, are included below.

Climate Division 5—High Plateau

Oregon's High Plateau, a region bordered by the Cascades on the west and several minor mountain ranges on the south and east, comprises much of Klamath County and parts of Lake and Deschutes Counties. Due to generally high elevations, the Plateau has cool temperatures and receives a significant amount of snow. Its distance from the coast, coupled with its location downwind of the Cascades, causes its annual precipitation to be lower than in the mountainous areas surrounding it.

The Cascade crest, running north-south at a longitude of about 122deg W, is lower in elevation in the High Plateau than in most parts of Oregon. Only one peak, Mt. Thielsen, exceeds 9,000 feet. As a result, the 'rain shadow' effect produced by the mountains is less dramatic in this zone than in areas to the north. Another notable difference between the High Plateau and the surrounding zones is its average elevation east of the Cascades. Whereas the places east of the northern and central Oregon Cascade peaks are typically 2,000 - 4,000 feet above sea level, the lower elevations of the High Plateau average about 5,500 feet.

As air moves from west to east over the Cascades in Zone 5, it begins to descend; the greater the descent, the drier the air becomes. While air parcels reaching Bend to the north have descended about 4,000 feet from the crest and are usually quite dry, similar air parcels moving into the High Plateau drop only about 2,000 feet. This difference is reflected in the average annual precipitation total for these two areas. Bend receives only about 12 inches per year, while points in the High Plateau receive more than 20 inches.

The remoteness and ruggedness of the High Plateau has resulted in low area population. Only a few small towns, including Chemult, Silver Lake, and Odell Lake, serve as population centers; none exceeds 1,000 residents, however. Primary economic enterprises in the area include tourism (such as Oregon's only national park, Crater Lake), livestock raising (primarily beef cattle and sheep), and agriculture (includes alfalfa hay, grass and legume seed crop, and wheat).

Normal precipitation values in Zone 5 are dependent upon west-east orientation and elevation. Crater Lake, in the west, receives an average of more than 65 inches per year, while Fremont and Summer Lake to the east receive about 12 inches. Crater Lake's elevation is about 2,000 feet higher than the latter stations. Figure 1 shows NOAA climate stations in Zone 5, which were in operation during the 1961-1990 period. Figure 2 shows the Deschutes County region from the Oregon annual precipitation map. Table 1 lists normal monthly and annual precipitation totals at the Zone 5 climate stations. Tables 2a and 2b list the average number of days with precipitation amounts exceeding certain thresholds.

Temperatures in Zone 5 vary considerably during each day and throughout the year. The Crater Lake weather station, highest in elevation, has the coolest temperatures. Average maximum temperatures at this point range from the high 60's in summer to the mid 30's in winter; lows are near 40 deg F in summer and high teens in winter (see Table 3). Summer Lake and Fremont are the warmest sites during the summer, and the latter has the coldest average low temperatures in winter.

The combination of high elevation and distance from the coast can produce cold temperatures in any month of the year for the High Plateau. Table 4 lists average monthly and annual snowfall total for the various stations. Table 5 list median frost dates, respectively for four different temperature thresholds. Table 6 lists the growing season (average number of days between these dates). All Zone 5 sites except Summer Lake have very short seasons (less than 2 months at 32 deg F). With such a short (and highly variable) season, it is little wonder that Zone 5 is not a major Oregon agricultural area.

Table 7 and 8 list average monthly and annual heating and growing degree days, respectively.

Climate Division 7 -- South Central Oregon

South Central Oregon, the largest of the Oregon climatic divisions, is a vast area of high desert prairie punctuated by a number of mountain ranges and isolated peaks. This region is predominantly livestock country; in addition to beef cattle, there are large numbers of sheep, dairy herds, horses, and swine. There are large amounts of land under irrigation as well, particularly in the Deschutes, Crook, Jefferson, and Klamath Counties. Among the major field crops grown are potatoes, alfalfa and other hay crops, mint, wheat, oats, barley, and onions. In the remaining counties comprising this zone (Grant, Harney, and Lake), irrigated acreage is much smaller; grazing lands and dry land farming predominate.

Figure 1 shows NOAA climate stations in Zone 7, which were in operation during the 1961-90 period. Figure 2 shows the Deschutes County region from the Oregon annual precipitation map. Most of this region receives relatively low amounts of precipitation. As can be seen in Table 1, most of the stations in Zone 7 receive less than 15 inches per year. However, some of the higher mountain sites receive significantly greater precipitation. For example, Steens Mountain in Harney County, whose summit is more than 9,000 feet above sea level, receives more than 40 inches per year at its higher elevations. Other mountainous locations are also known to receive high annual amounts. Most of the stations in Zone 7 receive their highest monthly precipitation in the winter months with a secondary maximum during late spring and early summer. For other locations, the precipitation is greatest during spring and summer. Stations near the Cascades (such as Sisters, Bend, Chiloquin, Klamath Falls, and Madras) tend to have annual distributions very similar to those in western Oregon: winter maximum are followed by a steady decrease, with lowest monthly averages in midsummer. Farther east, however, spring-summer peaks are much more pronounced. At Hart Mountain, for example, the four wettest months are March through June. The months of July through September are generally the driest of the year throughout the region. These months are characterized by isolated local thunderstorms. Some months are very wet and others almost completely dry.

Table 2a and 2b lists the average number of days with precipitation amounts exceeding certain thresholds.

Table 3 lists normal monthly temperatures for Zone 7 measurement stations. Summers are generally quite warm, although the relatively high elevations tend to moderate the temperatures somewhat. Pelton Dam and Dayville, with mean maximum temperatures in the 90's during the warmest summer months, are the hottest stations in this region. The coldest sites listed are Brothers, Hart Mountain, Sprague River, and Ochoco Ranger Station. It is certain that some of the higher elevations are colder than the areas listed here, however.

Table 4 lists average monthly and annual snowfall total for the various stations.

Tables 5 and 6 list median frost dates and mean growing seasons, respectively, for four different temperature thresholds.

Table 7 and 8 list average monthly and annual heating and growing degree days, respectively.

County Description

Established: Dec. 13, 1916
Population: 122,050
Area: 3,055 sq. mi.
Economy: Tourism, retail trade, forest products, recreational equipment, aviation, software and high technology.
County Seat: Bend
French-Canadian fur trappers of the Hudson's Bay Company gave the name Riviere des Chutes (River of the Falls) to the Deschutes River, from which Deschutes County took its name. In 1916 Deschutes County was created from a part of Crook County.
Deschutes County is the outdoor recreation capital of Oregon. With noble, snow-capped peaks dominating the skyline to the west and the wide-open high desert extending to the east, the beauty and uniqueness of Deschutes County captures the awe of locals and visitors alike. Deschutes County has grown into a bustling, exciting place where progress and growth are hallmarks. During the past ten years, Deschutes County has experienced the most rapid growth of any county in the state largely due to its invigorating climate and year-round recreation activities. Central Oregon offers downhill and cross-country skiing, snowboarding, fishing, hunting, hiking, rockclimbing, whitewater rafting, and golfing. Deschutes County is the host of diverse annual events including the Cascade Festival of Music, the Art Hop, Cascade Children's Festival, Pole Pedal Paddle, Sisters Rodeo, Sunriver Sunfest, and the Cascade Cycling Classic.

(County information obtained from Oregon Blue Book)
 

Climate Tables (Deschutes County, Oregon)


Table 1. Precipitation, Monthly and Annual Averages (1971-2000) (back to top)
Name
Number
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Annual
Bend
694
1.76
1.13
0.92
0.70
0.90
0.75
0.62
0.60
0.49
0.62
1.46
1.78
11.73
Brothers
1067
0.81
0.43
0.70
0.65
1.18
0.81
0.64
0.65
0.54
0.67
1.04
0.96
9.08
Redmond FAA AP
7062
0.97
0.68
0.76
0.65
0.95
0.62
0.55
0.54
0.37
0.56
0.98
0.92
8.55
Sisters
7857
2.32
1.72
1.17
0.89
0.79
0.60
0.45
0.50
0.48
0.98
2.14
2.15
14.19
Wickiup Dam
9316
3.46
2.59
2.01
1.32
1.17
1.01
0.81
0.84
0.81
1.33
3.12
3.56
22.03

Table 2a. Average number of Days with Selected Precipitation Amounts, Bend, 1971-2000 (back to top)
Threshold
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Annual
.01"or more
9.8
8.9
7.3
6.6
5.9
4.6
3.7
4.0
4.1
4.6
9.0
9.6
78.3
.10"or more
4.7
3.8
2.8
2.1
2.5
2.4
1.9
1.9
1.7
2.1
3.5
5.0
34.5
.50"or more
1.0
0.5
0.3
0.2
0.5
0.2
0.2
0.2
0.1
0.1
0.6
0.9
4.9
1.00"or more
0.2
0
0
0
0
0.1
0
0
0
0
0.2
0.2
0.9
Table 2b. Average number of Days with Selected Precipitation Amounts, Sisters, 1971-2000 (back to top)
Threshold
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Annual
.01"or more
8.7
8.1
7.9
7.5
6.4
4.4
2.8
3.3
3.4
5.4
10.4
8.5
78.7
.10"or more
5.2
4.9
4.0
2.6
2.3
1.6
1.1
1.7
1.4
2.7
4.9
4.8
37.9
.50"or more
1.4
0.8
0.5
0.3
0.4
0.2
0.2
0.2
0.1
0.4
1.2
0.9
6.0
1.00"or more
0.5
0.3
0
0.1
0.1
0
0.1
0
0.1
0.1
0.5
0.4
1.4

Table 3. Monthly and Annual Average Temperatures (deg F), Bend (1862), 1971-2000 (back to top)
Parameter
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Annual
Mean max
39.7
44.1
50.6
57.4
64.9
72.8
8-0.7
80.6
72.4
61.7
46.3
39.6
59.2
Mean min
22.6
24.7
27.2
30.0
35.6
41.2
46.2
45.6
38.6
32.2
27.6
22.7
32.9
Mean temp
31.2
34.4
38.9
43.7
50.3
57.0
63.5
63.1
55.5
47.0
37.0
31.2
46.1
Extreme max
67
73
76
86
92
95
98
102
100
90
74
66
102
Extreme min
-16
-17
-5
9
16
23
27
29
19
3
-10
-24
-24
Mean number of days
Max 90 or more
0
0
0
0
0.1
1.0
5.5
5.9
1.1
0
0
0
13.8
Min 32 or less
25.6
23.4
24.4
19.2
11.4
3.1
0.6
0.5
6.8
16.1
21.3
26.1
178.5
Max 32 or less
4.8
2.6
0.3
0
0
0
0
0
0
0.1
1.3
4.3
13.7
Min 0 or less
1.1
0.7
0.1
0
0
0
0
0
0
0
0.4
1.1
3.4

Table 4. Snowfall, Monthly and Annual Averages (1971-2000) (back to top)
Name
Number
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Annual
Bend
694
8.6
5.8
2.8
0.9
0.1
0
0
0
0
0.3
4.7
8.0
30.3
Brothers
1067
4.7
2.8
2.2
1.1
0.7
0
0
0
0
0.6
3.1
5.7
21.3
Redmond FAA AP
7062
4.3
3.1
1.6
0.6
0.1
0
0
0
0
0.2
3.0
4.6
19.3
Sisters
7857
8.3
9.6
3.4
0.3
0
0
0
0
0
0.2
4.8
7.6
42.5
Wickiup Dam
9316
18.8
16.6
10
4.2
0.5
0
0
0
0
1.7
11.7
18.1
79.3

Table 5. Median Spring and Fall Frost Dates, Bend, 1971-2000 (back to top)
Percentile
Last Date in Spring of Low Temperatures (deg F)
First Date in Fall of Low Temperatures (deg F)
24
28
32
36
24
28
32
36
10
19-Apr
7-May
1-Jun
17-Jun
23-Sep
9-Sep
2-Jul
1-Jul
20
22-Apr
12-May
7-Jun
19-Jun
27-Sep
12-Sep
5-Jul
3-Jul
50
8-May
30-May
19-Jun
25-Jun
11-Oct
19-Sep
31-Aug
6-Jul
80
22-May
13-Jun
26-Jun
29-Jun
22-Oct
3-Oct
14-Sep
7-Aug
90
26-May
18-Jun
29-Jun
30-Jun
26-Oct
7-Oct
21-Sep
24-Aug

Table 6. Average Growing Season, Bend, 1971-2000 (back to top)
Percentile
Length of Time (Days) Between Occurrence of Temperatures ( deg F)
24
28
32
36
10
126
78
11
4
20
136
97
18
7
50
149
110
70
15
80
175
135
92
40
90
190
150
101
65

Table 7. Monthly and Annual Average Heating Degree Days (base 65°F), 1971-2000 (back to top)
Name
Number
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Annual
Bend
694
1022
848
800
635
464
256
110
112
284
543
822
1025
6926
Brothers
1067
1157
952
905
706
528
305
140
150
340
615
931
1158
7831
Redmond FAA AP
7062
1021
820
770
597
424
205
75
77
236
512
817
1036
6658
Sisters
7857
1055
874
813
658
477
267
116
126
300
594
867
1076
7165
Wickiup Dam
9316
1148
955
911
718
523
295
133
139
320
603
902
1134
7761

Table 8. Monthly and Annual Average Growing Degree Days (base 50°F), 1971-2000 (back to top)
Name
Number
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Annual
Bend
691
0
1
5
32
104
233
424
415
208
69
5
0
1496
Brothers
1067
0
0
0
19
79
195
381
362
170
41
1
0
1248
Redmond FAA AP
7062
1
2
6
39
120
282
492
482
251
77
7
1
1760
Sisters
7857
0
1
2
21
89
216
406
391
187
39
2
0
1354
Wickiup Dam
9316
0
0
0
13
76
196
381
365
175
37
0
0
1243