klamath county climate
Introduction

Klamath County lies in the southern part of Oregon along the California border. It is within both 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 Klamath County. Climate tables for various parameters, as observed at long-term climate stations in Klamath 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 Klamath County mean annual precipitation (1971-2000 averages). 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 1961-1990 period. Figure 2 shows the Klamath 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: Oct. 17, 1882
Population: 64,200
Area: 6,135 sq. mi.
Economy: Forest products, agriculture, tourism and recreation.
County Seat: Klamath Falls

The Klamath or "Clamitte" tribe of Indians, for which Klamath County was named, has had a presence for 10,000 years. White settlement began in 1846 along the Applegate Immigrant Trail, which precipitated clashes between the two cultures and led to the Modoc Indian War of 1872. The Oregon Legislature created Klamath County by dividing Lake County in 1882. Linkville was named county seat and its name was changed to Klamath Falls in 1893. Klamath County's present-day position as a great lumber, agriculture and distribution center was assured in the early 1900s with the coming of the railroad and the start of one of the most successful of all federal reclamation projects—the Klamath Project, which drained much of the 128 square mile Lower Klamath Lake to provide 188,000 acres of irrigable land. Natural geothermal hot wells provide heat for many homes, businesses and the OIT campus. The full potential of this energy resource continues to be studied. Klamath is recognized for its scenic beauty, outdoor recreation, abundant waterfowl and diverse landscape.

(County information obtained from Oregon Blue Book)

Climate Tables (Klamath 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
Chemult 2 N
1546
4.16
3.04
2.56
1.26
1.14
0.82
0.59
0.67
0.83
1.32
3.8
4.17
24.36
Chiloquin 7 NW
1574
3.15
2.57
2.21
1.41
1.18
0.59
0.47
0.58
0.62
1.17
2.87
3.37
20.19
Crater Lake Natl Park
1946
9.81
8.47
7.79
5.34
3.50
2.03
0.95
1.07
2.21
4.49
10.53
10.5
66.69
Klamath Falls 2 SSW
4506
2.03
1.42
1.53
0.93
1.10
0.69
0.36
0.50
0.58
0.85
1.95
2.01
13.95
Sprague River
8007
2.36
1.79
1.93
1.05
1.15
0.71
0.47
0.55
0.68
1.07
2.06
2.26
16.08

Table 2a. Average number of Days with Selected Precipitation Amounts, Crater Lake Natl. Park, 1971-2000 (back to top)
Threshold
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Annual
.01"or more
16.8
16.8
18.5
14.6
10.7
7.3
4.1
4.3
5.8
9.3
17.6
17.1
143.9
.10"or more
14.1
14.2
15.0
11.3
8.0
4.9
2.3
2.9
4.4
7.3
14.9
15.1
115.2
.50"or more
7.6
7.2
5.8
4.1
2.6
1.3
0.6
0.6
1.3
3.6
8.0
7.8
50.8
1.00"or more
2.9
1.9
1.7
0.7
0.4
0.2
0.2
0
0.6
1.2
3.3
3.5
16.8
Table 2b. Average number of Days with Selected Precipitation Amounts, Klamath Falls SSW, 1971-2000 (back to top)
Threshold
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Annual
.01"or more
11.5
10.1
10.9
8.0
6.6
4.9
2.3
3.3
3.2
5.6
10.8
12.2
88.3
.10"or more
5.5
4.4
4.8
2.9
3.4
2.3
0.9
1.4
1.6
2.6
6.2
6.4
41.4
.50"or more
0.9
0.4
0.6
0.3
0.5
0.2
0.2
0.4
0.3
0.2
0.7
1.2
5.9
1.00"or more
0.2
0
0
0
0
0
0
0.1
0
0
0.1
0.1
0.6

Table 3. Monthly and Annual Average Temperatures (deg F), Klamath Falls 2 SSW (1862), 1971-2000 (back to top)
Parameter
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Annual
Mean max
39.9
45.7
51.8
59.3
68.2
77.1
85.7
85.2
77.0
64.6
47.4
39.5
61.8
Mean min
21.9
25.6
28.8
32.3
39.1
45.8
51.9
50.4
43.6
34.9
27.7
22.1
35.3
Mean temp
30.9
35.7
40.3
45.8
53.7
61.5
68.8
67.8
60.3
49.8
37.6
30.8
48.6
Extreme max
58
69
73
87
98
100
102
104
100
88
71
59
104
Extreme min
-9
-10
4
15
22
28
30
32
20
11
1
-17
-17
Mean number of days
Max 90 or more
0
0
0
0
0.6
2.5
11.4
10.5
2.2
0
0
0
27.8
Min 32 or less
26.8
22.7
21.6
16.0
6.1
0.7
0
0.1
1.7
11.8
22.3
27.2
156.6
Max 32 or less
4.8
1.0
0.1
0
0
0
0
0
0
0
0.9
4.6
11.0
Min 0 or less
0.8
0.3
0
0
0
0
0
0
0
0
0
0.8
1.6

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
Chemult 2 N
1546
24.4
23.4
11.2
3.6
0.5
0.1
0
0
0
1.0
17.2
24.9
130.9
Chiloquin 7 NW
1574
7.3
9.4
5.2
3.1
0.3
0
0
0
0
0.3
6.6
5.2
33.7
Crater Lake Natl Park
1946
83.5
82.3
74.9
45.2
18.9
4.3
0.3
0.2
4.0
19
71.1
79.8
490.2
Klamath Falls 2 SSW
4506
8.7
5.1
2.7
0.5
0.1
0
0
0
0
0.4
4.2
9.8
32.4
Sprague River
8007
10.5
7.3
5.9
1.7
0.5
0
0
0
0
0.2
4.9
10.2
39.2

Table 5. Median Spring and Fall Frost Dates, Klamath Falls 2 SSW, 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
30-Mar
29-Apr
19-May
5-Jun
30-Sep
18-Sep
30-Jul
2-Jul
20
10-Apr
3-May
22-May
11-Jun
17-Oct
29-Sep
28-Aug
4-Jul
50
21-Apr
14-May
4-Jun
19-Jun
27-Oct
13-Oct
21-Sep
26-Aug
80
6-May
28-May
11-Jun
25-Jun
8-Nov
21-Oct
5-Oct
21-Sep
90
16-May
1-Jun
18-Jun
26-Jun
10-Nov
23-Oct
11-Oct
1-Oct

Table 6. Average Growing Season, Klamath Falls 2 SSW, 1971-2000 (back to top)
Percentile
Length of Time (Days) Between Occurrence of Temperatures ( deg F)
24
28
32
36
10
158
121
62
13
20
165
130
73
20
50
190
146
117
70
80
206
164
126
96
90
216
169
135
112

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
Chemult 2 N
1546
1215
997
968
779
550
332
162
188
365
637
961
1208
8395
Chiloquin 7 NW
1574
1212
948
950
797
572
294
136
106
356
641
884
1114
0
Crater Lake Natl Park
1946
1204
1085
1147
989
828
586
358
328
475
738
1047
1190
9950
Klamath Falls 2 SSW
4506
1060
831
763
577
363
155
41
48
171
470
827
1062
6336
Sprague River
8007
1141
902
858
689
492
268
120
131
313
605
903
1137
7484

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
Chemult 2 N
1546
0
0
0
5
59
158
332
304
139
26
0
0
1023
Chiloquin 7 NW
1574
0
0
1
1
39
196
366
410
140
24
0
0
1177
Crater Lake Natl Park
1946
0
0
0
0
6
38
159
178
90
22
0
0
493
Klamath Falls 2 SSW
4506
0
0
5
40
170
350
586
550
322
91
2
0
2116
Sprague River
8007
0
0
1
14
81
216
398
380
175
34
1
0
1300