wallowa county climate

Introduction

Wallowa County lies along the northeastern part of the Washington border. It is wholly within Climate Division 8 (Northeast Oregon) established by the National Climatic Data Center. Below is a description of the climate of Division 8 followed by specific descriptions of Wallowa County. Climate tables for various parameters, as observed at long-term climate stations in Wallowa County, are included below.

Climate Division 8 — Northeast Oregon

Climate Zone 8 occupies the northeastern corner of Oregon, occupying all of Wallowa, Baker, and Union Counties as well as portions of Umatilla and Grant. The area includes several sizable mountain ranges with large valleys between them. Among the larger cities are La Grande, Baker City, John Day, and Enterprise, although the biggest of these (La Grande) has a population of only slightly above 10,000 residents.

Several million acres of Federal land are being utilized by ranchers for livestock which is the major industry in this region. Beef cattle are the main livestock raised, but sheep, dairy herds, poultry, and hogs are significant income sources as well. Field crops are also an important commodity and include wheat, potatoes, barley, oats, and grass seed. Lumber is also produced in significant quantities from the forested areas in the region.

Annual precipitation totals in Zone 8 valley areas are generally below 20 inches. Some locations surrounded by high mountains, such as Baker City and Unity, barely exceed 10 inches per year. High elevation sites, on the other hand, receive much larger annual totals. Locations near the top of the Wallowa Mountains, for example, may exceed 100 inches precipitation per year, much of it in the form of snow. Figure 1 shows NOAA climate stations in Zone 8, which were in operation during the 1961-1990 period. Figure 2 shows the Wallowa County region from the Oregon annual precipitation map. Table 1 lists monthly and annual normal precipitation at Zone 8 sites. Highest normal precipitation totals tend to be in winter and late spring. Unlike most of Oregon, Zone 8's monthly distribution in comparison is remarkably uniform throughout the year. Table 2 lists the average number of days with precipitation amounts exceeding certain thresholds.

Zone 8's distance from the ocean causes its annual temperature variations to be rather large. Table 3 lists normal monthly temperatures at stations in the area. Mean maximum temperatures are mostly in the 80's in summer months and in the 30's in winter. The dry, clear summer days are usually followed by cool nights; nighttime lows generally average in the 40's. The coldest temperatures in the region (and probably in the state) are observed in Seneca, located in a deep valley surrounded by mountain ridges. January low temperatures in Seneca average a cold 8.4 deg F. Annually, Seneca experiences an average of 22 days with below-zero temperatures. Seneca is in a tie for the coldest temperature ever recorded in Oregon, -54 deg F, set in February 1933.

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

Tables 5 and 6 list median frost dates and mean growing seasons, respectively, for four different temperature thresholds. While some of the lower valley sites have fairly long growing seasons, a few of the colder locations have very short seasons. At Seneca, Austin, and Ukiah, the mean length of time between freezing temperatures is less than six weeks.

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

County Description

Established: Feb. 11, 1887
Population: 7,100
Area: 3,153 sq. mi.
Economy: Agriculture, art, livestock, forest products and recreation.
County Seat: Enterprise

This rather isolated area was claimed by the Chief Joseph band of the Nez Perce as its hunting and fishing grounds. The Nez Perce used the word "wallowa" to designate a tripod of poles used to support fish nets. In 1871, the first white settlers came to Wallowa County, crossing the mountains in search of livestock feed in the Wallowa Valley. The area had been part of Union County since 1864 but it was carved from that county in 1887 by a legislative act. Wallowa County is a land of rugged mountains, gentle valleys and deep canyons. Peaks in the Wallowa Mountains soar to almost 10,000 feet in elevation and the Snake River dips to about 1,000 feet above sea level. Hells Canyon, carved by the Snake, is the nation's deepest gorge, averaging 5,500 feet from rim to river. The scenery in the county is spectacular and serves as a magnet for tourists. Unrivaled opportunities for outdoor recreation create the county's reputation as a visitors' paradise. Permanent residents enjoy the same recreation opportunities, adding to a high quality of life supported by traditional farm and forest industries as well as art and tourism.

(County information obtained from Oregon Blue Book)

Climate Tables (Wallowa 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
Enterprise 2 S
2675 1.17 1.07 1.51 1.72 2.15 1.97 1.08 1.21 0.89 0.84 1.56 0.93 15.76
Enterprise 20 NNE
2678 1.7 1.47 1.66 1.94 2.25 1.95 1.3 1.15 1.13 1.19 2.16 1.9 19.8
Wallowa
8997 1.84 1.44 1.3 1.39 1.76 1.44 0.94 0.89 1.09 1.33 2.07 1.91 17.4

Table 2. Average number of Days with Selected Precipitation Amounts, Wallowa, 1971-2000 (back to top)
Threshold
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
.01"or more
12.8 11.3 11.5 10 10.9 8.9 5.6 5.9 6.3 9.1 14.7 12.6 119.8
.10"or more
5.8 4.5 4.6 4.5 5.7 4.5 2.6 2.8 2.8 4.5 6.7 6.1 54.9
.50"or more
0.5 0.4 0.2 0.4 0.7 0.5 0.6 0.4 0.6 0.4 0.7 0.7 6
1.00"or more
0.1 0.1 0 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0 0.8

Table 3. Monthly and Annual Average Temperatures (deg F), Wallowa (1862), 1971-2000 (back to top)
Parameter
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Mean max
35.2 42.4 51.9 60.2 68.3 76.6 85.4 85.7 76.7 63.1 45.1 35.9 60.5
Mean min
18.7 22.2 27.3 31.7 37.5 42.9 46 44.7 37.3 30.2 26.1 19.4 32
Mean temp
27 32.3 39.6 46 52.9 59.8 65.7 65.2 57 46.7 35.6 27.7 46.3
Extreme max
64 67 79 90 95 101 106 104 100 89 74 62 106
Extreme min
-24 -27 -5 15 19 26 29 25 17 6 -22 -28 -28
Mean number of days
Max 90 or more
0 0 0 0 0.3 2.8 10.4 10.9 3 0 0 0 26.6
Min 32 or less
28.2 25 23.5 15.7 6.8 1.7 0.3 0.6 8.4 19.5 23.5 28.1 182.7
Max 32 or less
11.4 3.5 0.3 0 0 0 0 0 0 0 2.4 9.8 28.5
Min 0 or less
3.3 1.5 0.1 0 0 0 0 0 0 0 0.4 2.8 8.4

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
Enterprise 2 S
2675 9.7 8.3 7.2 4.5 1 0 0 0 0.1 1.4 8.7 8.3 48.8
Enterprise 20 NNE
2678 9.7 8.3 7.2 4.5 1 0 0 0 0.1 1.4 8.7 8.3 48.8
Wallowa
8997 12.8 7 3.4 1 0.1 0 0 0 0 0.3 6.7 10.2 41

Table 5. Median Spring and Fall Frost Dates, Wallowa, 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
16-Apr 2-May 25-May 15-Jun 17-Sep 10-Sep 24-Aug 7-Aug
20
18-Apr 13-May 2-Jun 21-Jun 22-Sep 11-Sep 28-Aug 11-Aug
50
1-May 24-May 17-Jun 8-Jul 30-Sep 15-Sep 5-Sep 23-Aug
80
10-May 2-Jun 29-Jun 14-Jul 11-Oct 24-Sep 13-Sep 1-Sep
90
13-May 8-Jun 8-Jul 23-Jul 16-Oct 2-Oct 17-Sep 4-Sep

Table 6. Average Growing Season, Wallowa, 1971-2000 (back to top)
Percentile
Length of Time (Days) Between Occurrence of Temperatures ( deg F)
24 28 32 36
10
137 102 58 37
20
143 105 62 42
50
153 116 83 47
80
168 133 96 55
90
177 138 104 59

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
Enterprise 2 S
2675 1295 1057 912 698 526 319 201 184 406 684 1030 1330 8647
Enterprise 20 NNE
2678 1295 1057 912 698 526 319 201 184 406 684 1030 1330 8647
Wallowa
8997 1192 931 792 574 385 185 65 74 258 573 891 1166 7129

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
Enterprise 2 S
2675 0 0 0 16 75 173 286 305 116 23 0 0 994
Enterprise 20 NNE
2678 0 0 0 16 75 173 286 305 116 23 0 0 994
Wallowa
8997 0 0 2 31 131 289 472 457 219 39 2 0 1642