/65 '5 Unbound issue tq c;. 9 11 Does not circulate Special Report 919 (i.13 May 1993

The Climate of Oregon Climate Zone 7 South Central Area

Property of OREGON STATE UNIVERSITY Library Serials Corvallis, OR 9 733 1-4503

Agricultural Experiment Station Oregon State University For additional copies of this publication, write:

George Taylor State Climatologist Oregon Climate Service Strand Agriculture Hall 326 Oregon State University Corvallis, OR 97331-2010 The Climate of Oregon

Climate Zone 7 South Central Area

George H. Taylor, State Climatologist Alexi Bartlett

Oregon Climate Service Oregon State University Corvallis, Oregon

March, 1993

Oregon Climate Zone Summary

Zone 7 -- South Central Area

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.

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. Figure 1 is a map showing estimated isopleths of annual precipitation in Zone 7 based on 1961-90 normals (Taylor, Daly, and Gibson, 1992). High elevation points can easily be spotted, since they correspond to high annual precipitation amounts.

Rho. Dam° i Mathes 0 Ohfiteltell 0 Chroviii• Merolla? OGthidY 0 °aces Shang 0 0 0 Prineville Redmond °Rend

°Beetrn Statics Drowsey 0 Olhothers •Burna WSOI AP

Squaw Rum Ero Stet 0 Sala a minx 0 Mathew Refuge HDQ Oe Ranch°

• WSO Station °Alkali Lake 1 OP•ranch Refuge Paisley Chiloquin °Andrews Weston Mine 0 °Sprague River Hart Mountain Refuge

Klamath Falls White horse Renck Le *mew 0 OAd.l °1""° Malin 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 maxima 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 2 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.

Median dates of low temperature thresholds in spring and fall are listed in Table 3, and Table 4 gives the length of the growing season at each station.

Oregon Climate Service 1993 Oregon Climate Zone 7 South Central Area

Table 1. Monthly and Annual Precipitation (inches) 1961-1990 Means

Elevation Name (feet) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year Adel Lake 4580 1.11 .98 .93 .87 .82 1.01 .42 .59 .58 .46 1.13 1.09 9.79 Alkali Lake 4330 .64 .52 .73 .79 1.10 1.14 .57 .75 .57 .70 .78 .70 9.11 Andrew Weston Mine 4780 2.13 1.79 2.14 1.52 1.12 .90 .53 .79 .96 1.00 2.38 2.55 17.86 Barnes 3970 1.22 .88 .97 .79 1.11 1.06 .71 .89 .60 .79 1.62 1.52 12.19 Bend 3650 1.83 .97 .92 .60 .77 .86 .49 .58 .47 .65 1.57 1.99 11.70 Brothers 4640 1.06 .49 .64 .64 1.05 .95 .52 .72 .49 .67 1.21 1.10 9.31 Burns 4140 .99 .76 1.01 .65 .98 .83 .40 .66 .56 .72 1.25 1.15 9.96 Chiloquin 4160 2.19 2.83 2.47 1.30 1.29 .65 .61 .57 .82 1.23 3.18 3.59 22.28 Dayville 2260 .77 .74 1.39 1.24 1.82 1.07 .52 .94 .48 .70 1.09 .83 11.80 Double 0 4140 1.03 .69 .84 .68 1.17 .98 .39 .84 .56 .78 1.09 1.10 10.98 Drewsey 3520 1.09 .94 1.12 .69 .84 .51 .31 .52 .51 .54 1.29 1.28 9.53 Fossil 2650 1.66 1.23 1.34 1.41 1.27 1.03 .49 .80 .84 1.16 1.92 1.80 15.11 Grizzly 3640 1.54 1.00 1.09 .97 1.23 1.04 .42 .77 .71 .88 1.79 1.36 12.40 Hart Mountain Refuge 5620 .87 .74 1.22 1.33 1.43 1.34 .43 .61 .82 .97 1.16 1.13 12.21 Keno 4120 2.66 1.95 2.07 1.11 1.15 .97 .36 .67 .73 1.54 2.88 3.21 19.31 Klamath Falls 4100 1.81 1.28 1.35 .75 .85 .69 .35 .62 .55 1.07 1.97 2.23 13.47 Madras 2230 1.33 .88 .84 .71 .79 .78 .44 .54 .54 .70 1.49 1.48 10.90 Malheur 2230 .89 .57 1.00 .71 1.06 .91 .40 .74 .51 .79 1.18 1.04 10.47 Malin 4630 1.50 1.18 1.60 1.02 1.14 .85 .38 .75 .79 1.15 1.60 1.50 13.59 Metolius 2500 1.32 .86 .86 .68 .76 .76 .38 .60 .47 .66 1.54 1.41 9.96 Mitchell 2650 .86 .65 1.04 1.13 1.55 1.25 .57 .78 .74 .75 1.23 .99 11.57 Ochoco Ranch 3980 2.13 1.55 1.37 1.13 1.24 1.29 .70 .88 .94 1.25 2.49 2.38 17.10 P Ranch Refuge 4200 1.05 .84 1.18 1.08 1.27 1.18 .39 .74 .76 .90 1.36 1.14 11.69 Paisley 4360 1.40 .84 .97 .75 .96 1.08 .39 .64 .50 .79 1.18 1.52 11.05 Paulina 3680 1.33 .88 1.03 .81 1.08 1.08 .61 .67 .53 .83 1.44 1.39 12.49 Pelton Dam 1410 1.52 .93 .85 .67 .67 .57 .29 .46 .47 .61 1.50 1.54 10.01 Prineville 2840 1.01 1.15 .99 .90 .98 .83 .76 .33 .62 .76 1.20 1.35 10.74 Redmond 3060 1.06 .60 .69 .58 .71 .73 .45 .54 .41 .54 1.16 1.09 8.62 Sisters 3180 2.55 1.66 1.23 .74 .55 .53 .41 .45 .49 .90 2.20 2.45 14.18 Sprague River 4360 2.45 1.52 1.81 .90 .99 .84 .34 .69 .68 1.33 2.24 2.34 16.97 Squaw Butte 4660 1.27 .72 .86 .73 1.13 .94 .36 .73 .52 .71 1.23 1.22 10.55 Whitehorse Ranch 4200 .59 .63 .83 .97 .77 .61 .24 .84 .59 .55 .82 .63 8.61

Oregon Climate Service 1993 Oregon Climate Zone 7 South Central Area

Table 2. Monthly Temperatures (°F) 1961-1990 Means

Station Code Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann Adel Lake Mean Maximum 41.9 46.6 52.3 59.3 - 69.9 78.4 87.9 86.2 77.8 67.1 50.2 42.1 63.7 Mean Minimum 21.8 24.3 27.8 31.7 39.1 46.6 52.1 50.1 42.0 34.0 27.7 21.5 35.4 Monthly Mean 31.8 35.4 40.1 45.5 54.5 62.5 70.0 68.1 59.9 50.6 39.0 31.8 49.5 Alkali Lake Mean Maximum 41.7 46.6 51.3 59.4 69.3 78.5 88.1 86.5 77.9 65.9 50.2 42.1 63.4 Mean Minimum 19.1 23.4 25.4 28.6 34.8 425 46.9 45.4 37.0 29.7 25.1 19.1 31.6 Monthly Mean 30.5 35.0 38.4 44.0 52.1 60.4 67.5 66.0 57.5 47.8 37.8 30.6 47.5 Andrew Weston Mine Mean Maximum 37.0 42.6 48.7 56.7 65.7 76.6 85.7 84.3 73.5 61.8 46.4 38.3 59.7 Mean Minimum 22.4 26.8 30.9 36.0 42.7 51.6 59.3 58.7 49.5 40.7 30.7 23.6 39.3 Monthly Mean 29.7 34.7 39.8 46.3 54.2 64. 72.5 71.5 61.6 51.3 38.5 30.9 49.5 Barnes Mean Maximum 38.4 44.3 49.7 57.3 66.0 74.9 - 84.1 82.9 74.8 63.7 47.2 39.2 60.1 Mean Minimum 17.8 22.8 25.5 28.1 34.1 41.0 45.3 44.2 36.8 30.1 25.3 18.8 30.8 Monthly Mean 28.1 33.5 37.6 42.7 50.1 58.0 64.7 63.6 55.7 46.9 36.2 29.0 45.4 Bend Mean Maximum 41.6 46.3 51.1 57.5 65.1 73.6 81.5 80.9 73.1 63.1 48.5 41.7 60.3 Mean Minimum 21.9 24.5 25.9 29.1 34.5 41.1 45.0 44.6 37.4 31.2 27.1 22.4 32.1 Monthly Mean 31.7 35.4 38.5 43.3 49.8 57.3 63.2 62.7 55.2 47.2 37.8 32.1 46.2 Brothers Mean Maximum 37.6 42.8 48.1 56.0 64.4 73.0 81.9 80.9 73.0 62.6 45.9 38.3 58.7 Mean Minimum 16.8 21.0 22.4 24.8 30.6 37.7 41.8 41.0 33.8 27.9 22.8 17.3 28.2 Monthly Mean 27.2 31.9 35.3 40.4 47.5 55.4 61.9 60.9 53.4 45.2 34.4 27.8 43.4 Burns Mean Maximum 33.2 38.4 47.8 57.8 64.9 74.4 84.2 83.6 73.3 61.1 44.1 33.1 59.4 Mean Minimum 12.7 17.1 26.7 29.4 36.3 41.7 47.2 45.3 36.5 28.1 21.3 12.2 30.3 Monthly Mean 23.0 27.8 37.3 43.6 50.6 58.0 65.7 64.5 54.9 44.6 32.7 22.7 44.9 Chiloquin Mean Maximum 35.9 40.3 48.5 57.7 64.3 72.7 79.8 80.5 71.9 62.1 44.8 36.2 58.1 Mean Minimum 17.3 19.8 26.3 29.3 32.6 39.1 42.3 41.8 35.7 29.6 24.8 18.7 29.8 Monthly Mean 26.6 30.0 37.4 43.5 48.5 55.9 61.0 61.1 53.8 45.8 34.8 27.4 43.9 Dayville Mean Maximum 45.7 49.3 57.8 65.7 72.4 82.0 90.6 90.1 80.5 68.3 51.7 41.4 71.4 Mean Minimum 28.2 26.5 33.6 37.2 42.6 48.9 52.9 52.4 45.4 39.3 31.1 23.2 41.7 Monthly Mean 36.9 37.8 45.7 51.5 57.5 65.0 71.7 71.3 63.0 53.8 41.4 32.8 56.6 Double 0 Mean Maximum 38.8 44.6 50.6 59.2 69.0 76.8 86.3 84.8 75.8 63.2 49.0 38.5 61.8 Mean Minimum 19.1 23.3 26.5 30.5 36.7 44.0 48.3 46.1 37.6 29.2 25.3 18.2 32.5 Monthly Mean 28.9 33.9 38. 44.9 52.9 60.3 67.3 65.4 56.6 46.2 37.2 28.3 47.2 Drewsey Mean Maximum 34.3 42.7 52.7 - 62.5 71.1 81.0 89.4 87.9 78.0 66.0 47.0 36.2 62.9 Mean Minimum 12.8 19.9 25.5 29.7 36.6 43.9 48.9 45.6 35.4 26.9 21.7 14.5 30.5 Monthly Mean 23.5 31.3 39.1 46.1 53.8 62.4 69.1 66.7 56.7 46.4 34.4 25.3 46.7 Fossil Mean Maximum 41.1 46.9 51.9 58.6 66.9 75.0 83.5 83.2 74.8 65.8 48.7 41.5 61.2 Mean Minimum 23.8 26.8 28.6 31.0 35.5 42.3 45.1 45.9 39.8 34.1 29.8 25.3 33.8 Monthly Mean 32.5 36.7 40.3 44.8 51.4 58.6 64.3 64.5 57.3 50.0 39.2 33.4 47.3 Grizzly Mean Maximum 40.4 45.0 49.5 55.6 63.6 73.2 81.9 81.8 72.6 62.6 47.4 40.8 59.6 Mean Minimum 21.6 24.5 25.4 27.4 32.4 39.2 42.1 42.4 36.9 31.4 27.3 22.0 31.2 Monthly Mean 31.0 34.7 37.5 41.5 48.0 56.2 62.0 62.1 54.7 46.9 37.3 31.4 45.1 Hart Mtn Refuge Mean Maximum 39.3 41.9 45.0 52.9 62.4 71.5 81.2 80.2 71.2 60.9 46.0 39.5 57.9 Mean Minimum 18.2 21.1 22.2 26.0 32.2 39.1 43.9 43.6 37.0 30.6 24.3 18.0 29.9 Monthly Mean 28.9 31.6 33.5 39.4 47.3 55.3 62.5 61.9 54.1 45.8 35.2 28.9 44.1 Keno Mean Maximum 33.2 41.4 45.2 51.8 65.1 76.1 83.1 81.6 0.0 70.7 44.5 33.9 0.0 Mean Minimum 18.3 22.3 25.6 25.9 33.3 42.0 47.1 43.8 0.0 31.2 27.7 15.9 0.0 Monthly Mean 25.8 31.9 35.4 39.9 49.2 59.1 65.9 63.6 0.0 51.0 36.1 24.9 0.0 Oregon Climate Service 1993 Table 2. Cont. South Central Area

Station Code Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann - Klamath Falls Mean Maximum 39.2 45.2 50.6 58.3 67.6 76.5 84.9 83.8 76.2 64.1 47.4 39.2 61.0 Mean Minimum 20.5 24.9 27.8 31.1 38.3 45.6 50.9 49.7 42.8 34.6 27.6 21.8 34.6 Monthly Mean 29.8 35.0 39.2 44.7 52.9 61.0 67.9 66.8 59.5 49.4 37.5 30.5 47.8 Madras Mean Maximum 42.6 49.5 55.7 62.8 70.8 79.4 87.0 86.6 78.0 66.2 50.7 42.8 64.5 Mean Minimum 23.2 26.4 28.2 31.4 36.7 43.2 46.3 45.8 39.3 32.2 28.8 23.9 33.7 Monthly Mean 32.9 38.0 41.9 47.3 53.8 61.3 66.7 _66.2 58.5 49.0 39.7 33.4 49.0 Malheur Mean Maximum 37.4 44.3 49.8 58.4 67.4 75.1 84.8 83.2 74.5 63.1 47.3 37.5 60.3 Mean Minimum 17.6 22.9 25.5 29.9 37.5 44.8 49.2 47.4 38.5 29.9 24.6 17.2 32.1 Monthly Mean 27.5 33.8 37.6 44.2 52.5 60.1 66.9 65.3 56.5 46.5 35.9 27.4 46.3 Malin Mean Maximum 403 44.4 48.7 56.3 - 65.9 74.8 83.0 82.1 73.9 62.4 47.2 40.2 59.9 Mean Minimum 21.7 25.0 27.0 30.5 36.7 43.8 48.9 48.0 41.7 34.9 27.7 22.2 34.0 Monthly Mean 31.0 34.7 37.8 43.4 51.3 59.3 65.9 65.0 57.8 48.7 37.4 31.2 47.0 Metolius Mean Maximum 40.8 47.1 53.5 59.8 67.9 76.5 84.3 84.0 75.5 63.7 48.6 40.8 61.8 Mean Minimum 23.3 26.4 27.8 30.5 36.0 42.2 45.4 45.1 39.3 33.2 28.9 23.7 33.4 Monthly Mean 32.1 36.7 40.6 45.2 52.0 59.4 64.9 64.5 57.4 48.4 38.8 32.2 47.6 Mitchell Mean Maximum 41.3 47.1 52.9 59.8 68.0 77.5 85.8 85.3 75.8 64.6 48.9 41.5 62.7 Mean Minimum 23.6 27.1 30.4 33.4 39.4 46.8 51.0 50.7 42.7 35.3 29.2 24.4 36.5 Monthly Mean 32.4 37.0 41.7 46.6 53.7 62.1 68.4 68.0 59.3 49.9 39.0 33.0 49.6 Ochoco Ranch Mean Maximum 35.3 41.1 47.9 55.7 63.7 72.6 81.1 81.7 73.4 61.4 43.3 35.6 58.2 Mean Minimum 15.3 18.8 22.9 26.3 31.5 37.6 40.1 39.6 33.8 28.4 23.9 17.7 28.4 Monthly Mean 25.2 30.0 35.4 41.0 47.6 55.1 60.6 60.6 53.6 44.9 33.6 26.6 43.4 P Ranch Refuge Mean Maximum 42.0 48.0 53.5 60.7 68.5 77.0 85.6 85.0 77.1 66.9 51.1 42.3 62.4 Mean Minimum 20.4 24.2 26.8 30.6 37.3 43.8 46.6 44.4 36.4 30.0 27.1 21.5 32.1 Monthly Mean 31.2 36.2 40.1 45.7 52.9 60.4 66.2 64.7 56.7 48.5 39.1 32.0 47.2 Paisley Mean Maximum 41.5 46.9 51.2 58.8 67.5 75.9 84.6 83.7 76.1 65.2 49.0 41.7 62.1 Mean Minimum 21.6 25.2 27.3 31.4 38.2 45.3 49.2 48.3 40.6 33.4 26.9 22.0 34.3 Monthly Mean 31.5 36.1 39.3 45.1 52.9 60.7 66.9 66.0 58.3 49.3 37.9 32.0 48.2 Paulina Mean Maximum 38.0 45.1 51.5 59.7 68.5 77.3 86.9 85.9 78.0 66.3 48.4 39.0 62.0 Mean Minimum 16.6 22.3 25.3 27.5 33.7 40.6 43.4 41.8 33.7 27.0 24.5 17.7 29.5 Monthly Mean 27.3 33.7 38.4 43.6 51.1 58.9 65.1 63.8 55.9 46.6 36.4 28.3 45.8 Pelton Dam Mean Maximum 45.0 52.3 59.6 66.7 75.7 84.5 92.6 91.8 82.7 69.7 53.2 44.6 68.3 Mean Minimum 25.8 28.7 31.0 34.4 40.3 47.0 50.7 50.4 43.7 36.2 31.9 26.5 37.2 Monthly Mean 35.3 40.5 45.3 50.6 58.0 65.7 71.7 71.1 63.3 52.8 42.5 35.4 52.7 Prineville Mean Maximum 43.5 48.5 55.6 63.3 69.4 77.5 85.6 86.1 76.0 65.7 50.0 41.6 63.5 Mean Minimum 23.2 24.4 27.1 29.5 35.2 41.1 43.3 41.8 35.5 30.4 26.6 20.1 31.5 Monthly Mean 33.4 36.4 41.4 46.4 52.3 59.3 64.5 63.9 55.8 48.0 38.3 30.8 47.5 Redmond Mean Maximum 41.2 47.1 52.7 59.2 67.2 76.7 85.1 84.1 75.0 64.3 49.0 41.7 61.7 Mean Minimum 21.5 24.9 26.2 28.9 34.8 421 46.3 46.1 38.6 32.2 273 21.8 32.4 Monthly Mean 31.3 36.0 39.5 44.1 51.0 59.4 65.7 65.1 56.8 48.3 38.1 31.8 47.1 Sisters Mean Maximum 41.4 46.2 51.3 57.0 65.6 75.1 83.6 83.0 74.7 63.3 47.7 41.0 61.4 Mean Minimum 20.8 23.7 25.5 27.7 32.7 38.9 41.3 41.2 34.5 28.9 25.6 20.3 30.5 Monthly Mean 31.1 34.9 38.4 42.3 49.1 57.0 62.5 62.0 54.5 46.0 36.6 30.7 45.9 Sprague River Mean Maximum 39.0 44.7 49.6 57.5 67.1 75.9 84.5 84.1 76.5 65.4 47.9 39.5 60.5 Mean Minimum 15.7 20.6 23.6 25.3 31.2 38.1 41.5 40.4 32.8 26.9 22.9 17.3 27.7 Monthly Mean 27.4 32.7 36.6 41.4 49.1 57.1 63.0 62.2 54.6 46.2 35.4 28.4 44.1 Squaw Butte Mean Maximum 35.4 41.5 46.5 55.5 63.9 74.1 83.4 82.4 73.8 62.1 45.7 37.3 59.1 Mean Minimum 17.5 22.7 25.2 29.5 35.6 43.8 50.2 49.5 42.5 34.4 26.3 20.7 33.9 Monthly Mean 26.3 32.2 35.8 42.5 49.7 59.0 66.7 66.0 58.2 48.1 36.0 28.7 46.7 Oregon Climate Service 1993 Oregon Climate Zone 7 South Central Area

Table 3. Median Frost Dates 1961-1990 Means

Median Dates of Last Occurrence in Spring of Median Dates of First Occurrence in Fall of Station 24° F 28° F 32° F 36° F 24° F 28° F 32° F 36° F Adel 22-Apr 6-May 1-Jun 7-Jun 17-Oct 4-Oct 17-Sep 10-Sep Alkali Lake 12-May 25-May 18-Jun 8-Jul 2-Oct 12-Sep 3-Sep 19-Aug Andrew Weston Mine 13-Apr 6-May 16-May 6-Jun 8-Nov 28-Oct 7-Oct 26-Sep Barnes STN 14-May 4-Jun 28-Jun 16-Jul 30-Sep 11-Sep 2-Sep 15-Aug Bend 13-May 1-Jun 6-Jul 16-Jul 4-Oct 15-Sep 4-Sep 20-Aug Brothers 25-Jun 11-Jul 21-Jul 25-Jul 8-Sep 16-Aug 8-Aug 4-Aug Burns WSO 1-May 21-May 6-Jun 29-Jun 7-Oct 22-Sep 16-Sep 27-Aug Drewsey 10-May 22-May 22-Jun 2-Jul 26-Sep 14-Sep 3-Sep 20-Aug Fossil 5-May 24-May 8-Jun 10-Jul 9-Oct 2-Oct 11-Sep 26-Aug Grizzly 20-May 8-Jun 9-Jul 22-Jul 4-Oct 15-Sep 28-Aug 6-Aug Hart Mountain Refuge 31-May 21-Jun 7-Jul 19-Jul 21-Sep 11-Sep 23-Aug 14-Aug Klamath Falls 2 SSW 29-Apr 19-May 6-Jun 29-Jun 22-Oct 6-Oct 20-Sep 9-Sep Lakeview 29-Apr 17-May 3-Jun 29-Jun 14-Oct 4-Oct 20-Sep 29-Aug Madras 2-May 22-May 7-Jun 2-Jul 6-Oct 1-Oct 10-Sep 1-Sep Malheur Refuge 30-Apr 14-May 1-Jun 28-Jun 2-Oct 19-Sep 5-Sep 27-Aug Malin 2-May 20-May 11-Jun 30-Jun 27-Oct 3-Oct 21-Sep 3-Sep Metolius 4-May 23-May 8-Jun 7-Jul 14-Oct 28-Sep 11-Sep 24-Aug Mitchell 2 NW 10-Apr 4-May 24-May 3-Jun 28-Oct 16-Oct 30-Sep 16-Sep Ochoco Ranger STN. 20-May 20-Jun 11-Jul 26-Jul 2-Oct 8-Sep 15-Aug 2-Aug 00 Ranch 30-Apr 21-May 10-Jun 28-Jun 4-Oct 21-Sep 10-Sep 29-Aug Paisley 1-May 15-May 6-Jun 30-Jun 14-Oct 23-Sep 9-Sep 31-Aug Paulina 21-May 8-Jun 3-Jul 22-Jul 17-Sep 8-Sep 23-Aug 9-Aug P Ranch Refuge 28-Apr 16-May 3-Jun 1-Jul 25-Sep 12-Sep 3-Sep 19-Aug Redmond FAA AP 8-May 29-May 28-Jun 10-Jul 13-Oct 24-Sep 9-Sep 19-Aug Sisters 23-May 29-Jun 14-Jul 26-Jul 18-Sep 8-Sep 17-Aug 4-Aug Sprague River 28-May 25-Jun 12-Jul 22-Jul 17-Sep 30-Aug 18-Aug 3-Aug Squaw Butte Exp. Stn. 6-May 25-May 27-Jun 2-Jul 17-Oct 6-Oct 12-Sep 2-Sep Suntex 16-May 8-Jun 3-Jul 13-Jul 22-Sep 10-Sep 27-Aug 15-Aug Whitehorse Ranch 4-May 19-May 8-Jun 28-Jun 9-Oct 25-Sep 16-Sep 8-Sep

Oregon Climate Service 1993 Oregon Climate Zone 7 South Central Area

Table 4. Growing Season 1961-1990 Means

Average Days Between Occurrences of Station 24° F 28° F 32° F 36° F Adel 182 147 117 90 Alkali Lake 140 116 79 45 Andrew Weston Mine 209 171 140 106 Barnes STN 136 96 65 34 Bend 147 103 59 34 Brothers 83 46 23 13 Bums WSO 156 127 99 63 Drewsey 146 115 77 56 Fossil 158 131 90 46 Grizzly 141 105 58 32 Hart Mountain Refuge 115 79 46 27 Klamath Falls 2 SSW 179 141 104 69 Lakeview 167 138 107 64 Madras 160 133 93 60 Malheur Refuge 157 125 95 61 Malin 171 135 98 60 Metolius 163 129 93 48 Mitchell 2 NW 204 165 131 97 Ochoco Ranger STN. 133 79 41 15 00 Ranch 155 120 88 63 Paisley 163 132 91 58 Paulina 122 89 51 23 P Ranch Refuge 157 121 91 51 Redmond FAA AP 155 117 77 45 Sisters 128 75 37 14 Spaque River 108 74 46 27 Squaw Butte Exp. Stn. 163 134 85 58 Suntex 132 89 53 34 Whitehorse Ranch 161 132 105 79

Oregon Climate Service 1993