Malheur Experiment Station
Oregon State University
Information for Sustainable Agriculture


1995 Weather Report

J. Mike Barnum, Erik Feibert, and Clint Shock

Malheur Experiment Station

Oregon State University

Ontario, Oregon

Introduction

Daily observations of air temperature and precipitation have been recorded at the Malheur Experiment Station since July 20, 1942. Installation of additional equipment in 1948 allowed for evaporation and wind measurements. A recording soil thermometer was added in 1967. A biophenometer, to monitor growing degree days, and pyranometers, to monitor solar and photosynthetic active radiation, were added in 1985.

Since 1962, daily readings from the station have been reported to the U.S. Department of Commerce, Environmental Science Service Administration, National Weather Service. Each day the 8:00 a.m. air temperature, preceding 24-hour air and soil temperature extremes, and 24-hour accumulated precipitation are recorded and transmitted to radio station KSRV in Ontario. KSRV then conveys this information, along with their own daily readings, to the U.S. Weather Station in Boise, Idaho. During the irrigation season (April -October), evaporation, wind, and water temperature are also monitored and reported.

On June 1, 1992, in cooperation with the U.S. Bureau of Reclamation, a fully automated weather station, connected by satellite to the Northwest Cooperative Agricultural Weather Network (AgriMet) computer in Boise, Idaho, began transmitting data from Malheur Experiment Station. The automated station monitors air temperature, relative humidity, dew point temperature, precipitation, wind run, wind speed, wind direction, solar radiation, and soil temperature at 8-inch and 20-inch depths. Stored data is dumped and transmitted to the Boise computer every 4 hours. The database may be accessed via computer modem. During the irrigation season, daily Malheur County crop water-use estimates, which are based on data from this automated weather station, are also available by modem.

1995 Weather

Total precipitation for the year exceeded the 10-year and 53-year station averages by 43.5 percent and 32.8 percent , respectively (Table 1). With the exception of February, monthly precipitation totals from January through July were above both the 10-year and 53-year means (Table 2). Compared to the long term averages, January and December were abnormally wet (Figure 1). Precipitation accumulation for the fall/winter period October 1, 1994, through March 31, 1995, was 150 percent of the 53-year mean (Table 3).

Snowfall totals for January, February, March, October, and November were below the long-term means. Total snowfall accumulation for December was 149 percent of the 53-year average (Table 4). Annual snowfall for 1995 totaled 75 percent and 78 percent of the 10-year and 53-year averages, respectively (Table 5).

Mean monthly maximum air temperatures from April through August were consistently below the long term station means (Table 6). Mean monthly minimum air temperatures for the same period ranged from 1°F above to 4°F below the 53-year monthly means.

From March through August, monthly mean 4-inch soil temperatures tended to be slightly above the long term means (Table 7). From May through August mean monthly 4-inch soil temperature ranged from 1°F to 4°F above the 29-year monthly mean.

Monthly pan-evaporation totals for April through August ranged from 0.67 inches to 1.42 inches below the monthly mean totals for the past 10 years (Table 8). Mean 1995 daily pan-evaporation from March 1 through August 31 was approximately 0.27 inches per day. Monthly wind-run totals for April 1 through October 31 ranged from 2,449 miles for April to 1,532 miles for September (Table 9). The average daily wind-run over the irrigation season (April through October) was 63 miles per day. The average daily wind-run for the calendar year was 61 miles per day. Total pan-evaporation for the season was 9 percent under the 10-year mean and 5 percent over the 48-year mean (Table 10). Total wind-run for the season exceeded the 10-year mean by 4 percent and 48-year mean by 27 percent. The below-average evaporation figure for 1995 resulted from the occurrence of above-average precipitation amounts and below-average air temperatures throughout most of the irrigation season.

Seasonal estimates of crop water-use for those crops commonly grown in northeastern Malheur County, measured by the Bureau of Reclamation - AgriMet weather station at MES, estimated that crop water requirements for 1995 were below the average requirement for the past 4 years (Table 11).

The last spring frost (<32°F) occurred 10 days earlier than the 20-year mean date of April 26; the first fall frost occurred on September 22, 12 days earlier than normal. Table 12 shows the dates of the last spring and first fall occurrences of minimum air temperatures equal to or below threshold levels of 24, 28, 32, and 36 degrees Fahrenheit for the past 20 years. Table 13 shows the number of days between the last spring occurrence and the first fall occurrence of those threshold temperatures.

Total cumulative growing-degree-days (>50°F and <86°F) for the year were 11 percent below the 10-year mean (Table 14). Although cumulative growing degree days at the end of March were near to the 10-year mean (Figure 2), below-average temperatures from April through September reduced the overall growing-degree-day accumulation.

Record weather events recorded over the 53-year history for the Malheur Experiment Station are listed in Table 15.

Table 1. Annual precipitation totals for 1986 through 1995 and 10-year and 53-year mean annual precipitation totals at Malheur Experiment Station, Oregon State University, Ontario, Oregon.
  1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 10 yr mean 53 yr mean
   inches 
Total 8.64 9.81 7.58 9.15 7.21 9.25 8.64 13.3 10.05 14.01 9.76 10.55

Table 2. Daily and monthly precipitation totals for 1995 and 10-year and 53-year mean monthly precipitation totals at Malheur Experiment Station, Oregon State University, Ontario, Oregon.
Day Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
   inches 
1    0.02      0.04             0.01
2   0.08      0.48              
3     0.14   0.02 0.08 0.03          
4     0.20           0.03 0.18   0.06
5     T   0.10       0.04      
6 0.06   T 0.03 0.48 0.08           0.32
7 0.29     0.27 0.02 0.01   T     0.02 0.10
8 0.09     0.13       0.02     0.01  
9 0.20   0.12       0.17       0.07 T
10 0.03   0.03   T   0.09       T 0.11
11 0.10 0.06 0.03 0.06 0.21         0.06 T 0.05
12 0.19 0.07 0.05 0.02 T   0.03     0.11   0.45
13 0.57 0.01 0.20 0.03     0.46       0.11 T
14 0.19 T 0.13 T             0.02 0.10
15 0.06   0.09               0.03 0.22
16 0.02       0.06 0.06   0.02     T 0.23
17   0.03       0.46   0.09     0.02  
18 T 0.01 0.11     0.44       0.09 0.02  
19 0.19   0.32     0.38 0.02          
20 0.01   T 0.25   0.09            
21     T 0.12                
22     0.02             0.01    
23     0.14               T  
24                     0.01  
25                     0.02 T
26 0.12                 0.12 0.03 0.03
27                     T 0.01
28 T     0.06             0.48 0.02
29 0.03     0.01     0.05   T     0.15
30       0.18     0.25       0.04 0.41
31 0.52                     0.29
1995

total

 2.67 0.28 1.58 1.16 1.41 1.60 1.10 0.13 0.07 0.57 0.88 2.56
10 year mean 1.22 0.85 1.09 0.97 1.04 0.94 0.28 0.29 0.30 0.60 1.18 1.01
53 year mean 1.32 0.94 0.97 0.80 1.00 0.82 0.22 0.43 0.50 0.71 1.20 1.33

Table 3. Monthly fall and winter (October through March) precipitation totals from January 1986 through December 1995, and 10-year and 53-year mean monthly and mean seasonal precipitation totals for that six month period at Malheur Experiment Station, Oregon State University, Ontario, Oregon.
    1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 10-year 53-year
Month 1986 / 87 / 88 / 89 / 90 / 91 / 92 / 93 / 94 / 95   mean mean
   inches 
Oct - 0.12 0 0 0.86 0.49 1.01 0.95 0.80 1.23 0.57 1.22 1.32
Nov - 0.22 1.40 2.45 0.24 0.69 1.71 1.15 0.64 2.46 0.88 0.85 0.94
Dec - 0.22 1.46 1.48 0.01 0.29 0.43 1.51 0.60 1.49 2.56 1.09 0.97
Jan 0.96 1.24 1.25 0.88 0.44 0.59 0.58 2.35 1.20 2.67 - 0.60 0.71
Feb 2.29 0.77 0.14 1.27 0.35 0.44 1.36 1.02 0.57 0.28 - 1.18 1.20
Mar 1.24 1.37 0.26 2.17 0.72 0.88 0.25 2.41 0.05 1.58 - 1.01 1.33
Fall1   0.56 2.86 3.93 1.11 1.47 3.15 3.61 2.04 5.18 4.01 3.16 3.23
Spring2 4.49 3.38 1.65 4.32 1.51 1.91 2.19 5.78 1.82 4.53   2.79 3.24
Total   3.94 4.51 8.25 2.62 3.38 5.34 9.39 3.86 9.71   5.95 6.47

Table 4. Daily and monthly snowfall totals for 1995 and 10-year and 53-year mean monthly snowfall totals at Malheur Experiment Station, Oregon State University, Ontario, Oregon.
Day  Jan Feb Mar Oct Nov Dec
   inches 
1            
2            
3            
4            
5            
6 0.5         2.5
7 4.0         0.5
8 T          
9            
10            
11   T        
12   1.0        
13   1.0        
14   T        
15            
16            
17            
18 T          
19            
20            
21            
22            
23            
24            
25            
26           T
27           T
28         T T
29           1.5
30           4.0
31            
1995

total

 4.5 2.0 0 0 0 8.5
10 year

mean

 7.8 3.1 0.6 0.1 2.2 6.3
53 year

mean

 7.8 2.8 0.7 0.1 2.1 5.7

Table 5. Annual snowfall totals for 1986 through 1995 and 10-year and 53-year mean annual snowfall totals at Malheur Experiment Station, Oregon State University, Ontario, Oregon.
  1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 10 yr mean 53 yr 
mean
   inches
Total 13.0 15.5 34.8 25.1 5.7 7.5 15.5 36.0 32.0 15.0 20.0 19.2

Table 6. Daily maximum and minimum and monthly mean maximum and minimum air temperatures for 1995 and the 10-year and 53-year mean monthly maximum and minimum air temperatures at Malheur Experiment Station, Oregon State University, Ontario, Oregon.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Day max min max min max min max min max min max min max min max min max min max min max min max min
   inches
1 24 1 48 38 52 24 69 43 65 33 86 52 89 57 85 47 91 48 68 40 51 24 59 47
2 21 2 57 34 49 26 57 36 58 45 85 52 92 59 94 56 95 50 68 36 48 13 60 30
3 20 0 58 31 47 31 62 33 63 42 83 53 83 52 95 60 93 54 69 36 46 13 51 25
4 11 0 50 31 50 36 70 37 66 45 83 51 79 52 95 63 93 58 59 41 47 14 50 24
5 23 9 51 32 50 31 74 39 65 48 85 53 82 52 96 60 91 53 61 29 45 16 49 23
6 29 19 52 29 47 24 68 37 57 47 62 39 89 58 100 62 84 50 61 30 54 32 30 17
7 33 23 44 28 45 23 55 41 56 48 58 36 90 56 96 60 86 53 63 35 54 38 29 17
8 35 26 48 34 54 25 63 36 66 49 70 39 92 57 74 43 77 46 67 30 46 34 37 16
9 42 31 53 31 52 34 52 34 64 43 75 51 94 60 77 43 77 47 65 30 51 36 30 16
10 46 38 54 29 60 44 55 30 72 48 71 42 88 62 85 47 80 47 68 34 49 27 33 28
11 54 35 53 27 60 44 59 33 70 49 82 48 89 58 90 51 84 47 63 37 47 27 38 30
12 46 32 32 15 60 41 59 37 63 40 83 49 88 60 82 46 88 47 65 36 49 35 52 32
13 46 32 33 26 57 40 65 38 62 43 87 56 67 48 88 45 90 49 59 27 50 37 65 37
14 44 32 34 20 56 42 53 32 64 40 83 54 76 51 76 42 92 47 60 29 52 42 47 28
15 50 32 33 23 60 43 54 25 70 43 79 51 85 58 86 46 90 47 66 29 51 45 47 29
16 48 31 38 24 56 32 55 30 75 50 70 54 89 57 93 53 92 52 69 28 53 37 43 32
17 45 26 39 24 56 30 61 35 74 52 80 54 93 58 66 50 91 53 72 33 49 39 44 24
18 39 26 45 31 63 34 61 42 77 44 73 48 93 62 74 44 87 51 68 33 52 34 39 24
19 38 31 51 35 55 38 60 34 74 44 69 46 96 66 77 43 89 52 62 29 60 33 41 22
20 41 31 65 32 56 40 56 37 75 43 63 40 94 59 85 45 84 55 62 28 48 30 38 22
21 40 35 62 35 62 34 51 36 81 47 69 43 94 59 91 54 79 42 57 29 53 30 35 23
22 39 22 61 33 52 31 62 39 82 53 73 50 95 60 96 58 67 30 57 34 47 30 35 20
23 40 23 61 34 52 36 66 38 78 52 78 53 90 61 96 63 73 32 59 24 53 29 39 16
24 37 26 63 33 49 29 70 39 78 45 85 53 93 61 95 55 80 37 60 23 50 27 28 17
25 43 32 64 34 48 28 75 46 79 47 89 57 93 57 87 51 77 46 64 32 51 35 23 20
26 41 33 65 42 50 29 70 37 80 48 92 60 95 60 89 50 77 43 60 36 50 36 25 21
27 48 31 62 36 54 29 M M 75 44 95 62 91 58 89 51 75 50 65 35 53 28 26 22
28 46 29 54 27 57 28 74 40 77 47 85 55 95 62 88 46 74 45 59 29 45 30 26 21
29 41 32     56 27 66 42 83 48 84 49 100 63 89 52 71 43 60 28 41 34 33 23
30 45 35     56 26 57 42 87 52 84 49 79 48 81 47 69 38 62 32 56 37 32 26
31 45 37     63 29     90 55     79 47 86 46     53 23     34 27
1995
mean		 39 26 51 30 54 33 62 37 72 46 79 50 89 57 87 51 83 47 63 31 50 31 39 24
10 yr
mean		 33 16 42 22 55 32 66 38 74 46 83 53 90 57 89 54 80 46 67 35 46 26 36 18
53 yr
mean		 34 19 43 25 54 31 64 37 74 45 82 52 91 57 89 55 80 46 65 36 47 28 37 22

Table 7. Daily maximum and minimum and monthly mean maximum and minimum 4-inch soil temperatures for 1995 and the 10-year and 29-year mean monthly maximum and minimum 4-inch soil temperatures at Malheur Experiment Station, Oregon State University, Ontario, Oregon.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Day max min max min max min max min max min max min max min max min max min max min max min max min
  inches 
1 34 34 41 39 53 39 64 45 70 50 86 69 89 69 90 69 87 68 68 58 52 41 49 46
2 32 32 43 40 51 39 54 44 57 52 85 68 92 72 91 70 88 69 71 57 51 37 49 40
3 30 30 50 39 48 39 62 40 61 49 85 55 81 70 93 75 86 71 70 56 49 36 44 37
4