2005 WEATHER REPORT



Erik B. G. Feibert and Clinton C. Shock

Malheur Experiment Station

Oregon State University

Ontario, OR

Introduction

Air temperature and precipitation have been recorded daily at the Malheur Experiment Station since July 20, 1942. Installation of additional equipment in 1948 allowed for evaporation and wind measurements. A soil thermometer at 4-inch depth was added in 1967. A biophenometer, to monitor degree days, and pyranometers, to monitor total solar and photosynthetically active radiation, were added in 1985.

Since 1962, the Malheur Experiment Station has participated in the Cooperative Weather Station system of the National Weather Service. The daily readings from the station are reported to the National Weather Service forecast office in Boise, Idaho.

Starting in June 1997, the daily weather data and the monthly weather summaries have been posted on the Malheur Experiment Station web site on the internet at www.cropinfo.net.

On June 1, 1992, in cooperation with the U.S. Department of the Interior, Bureau of Reclamation, a fully automated weather station, linked by satellite to the Northwest Cooperative Agricultural Weather Network (AgriMet) computer in Boise, Idaho, began transmitting data from Malheur Experiment Station. The automated station continually 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. Data are transmitted via satellite to the Boise computer every 4 hours and are used to calculate daily Malheur County crop water-use estimates. The AgriMet database can be accessed through the internet at www.usbr.gov/pn/agrimet and is linked to the Malheur Experiment Station web page at www.cropinfo.net.

Methods

The ground under and around the weather stations was bare until October 17, 1997, when it was covered with turfgrass. The grass is irrigated with subsurface drip irrigation. The weather data are recorded each day at 8:00 a.m. Consequently, the data in the tables of daily observations refer to the previous 24 hours.

Evaporation is measured from April through October as inches of water evaporated from a standard class A pan (10-inch-deep by 4-ft-diameter) over 24 hours. Evapotranspiration (ETc) for each crop is calculated by the AgriMet computer using data from the AgriMet weather station and the Kimberly-Penman equation (Wright 1982). Reference evapotranspiration (ET0) is calculated for a theoretical 12- to 20-inch-tall crop of alfalfa assuming full cover for the whole season. Evapotranspiration for all crops is calculated using ET0 and crop coefficients for each crop. These crop coefficients vary throughout the growing season based on the plant growth stage. The crop coefficients are tied to the plant growth stage by three dates: start, full cover, and termination dates. Start dates are the beginning of vegetative growth in the spring for perennial crops or the emergence date for row crops. Full cover dates are typically when plants reach full foliage. Termination dates are defined by harvest, frost, or dormancy. Alfalfa mean ETc is calculated for an alfalfa crop assuming a 15 percent reduction to account for cuttings.

Wind run is measured as total wind movement in miles over 24 hours at 24 inches above the ground. Weather data averages in the tables, except evapotranspiration, refer to the years preceding and up to, but not including, the current year.

2005 Weather

The total precipitation for 2005 (14.25 inches) was higher than the 10-year (10.38 inches) and 60-year (10.19 inches) averages (Table 1). Precipitation in May (2.94 inches) was over twice as high as the 10-year and 60-year averages and was the third highest since observations began in 1943 (1st: 4.55 inches in May 1998, 2nd: 3.09 inches May 1953). The months of October, November, and December had precipitation higher than average. Precipitation in December (3.92 inches) was over twice as high as the 10-year and 60-year averages and was the highest since observations began in 1943. Total snowfall for 2005 (14 inches) was lower than the 10-year (14.0 inches) and 62-year averages (18.2 inches) (Table 2).

The highest temperature for 2005 was 101°F on August 6 and 7 (Table 3). The lowest temperature for the year was -2°F on December 18. The average maximum and minimum air temperatures for December were substantially lower than the 10-year and 60-year averages.

The months of April, May, and June had a lower number of growing degree days (50° to 86°F) than the 19-year average (Table 4, Fig. 1). June had 19 percent fewer growing degree days than the 19-year average. The total number of degree days in the above-optimal range in 2005 was close to the average (Table 5).

All months, except April, had total wind runs lower than the 10-year and 57-year averages (Table 6). Total pan-evaporation for 2005 was close to the 10-year and 56-year averages (Table 7). Total accumulated ETc for all crops in 2005 was close to the 14-year average (Table 8).

The average monthly maximum and minimum 4-inch soil temperatures in 2005 were close to the 10-year and 37-year averages (Table 9).

The last spring frost ([32°F) occurred on April 15, 13 days earlier than the 29-year average date of April 28; the first fall frost occurred on October 6, 1 day later than the 29-year average date of October 5 (Table 10).

No other weather records were broken in 2005 (Table 11).

References

Wright, J.L. 1982. New evapotranspiration crop coefficients. J. Irrig. Drain. Div., ASCE 108:57-74.

Table 1. Monthly precipitation at the Malheur Experiment Station, Oregon State University, Ontario, OR, 1991-2005.

Year

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Total


-------------------------------------------------------- inches --------------------------------------------------------

1991

0.59

0.44

0.88

0.81

1.89

1.09

0.01

0.04

0.35

1.01

1.71

0.43

9.25

1992

0.58

1.36

0.25

0.74

0.21

1.43

0.36

0.01

0.09

0.95

1.15

1.51

8.64

1993

2.35

1.02

2.41

2.55

0.70

1.55

0.18

0.50

0.00

0.80

0.64

0.60

13.30

1994

1.20

0.57

0.05

1.02

1.62

0.07

0.19

0.00

0.15

1.23

2.46

1.49

10.05

1995

2.67

0.28

1.58

1.16

1.41

1.60

1.10

0.13

0.07

0.57

0.88

2.56

14.01

1996

0.97

0.86

1.03

1.19

2.39

0.12

0.32

0.31

0.59

0.97

1.18

2.76

12.69

1997

2.13

0.17

0.25

0.66

0.67

0.86

1.40

0.28

0.40

0.43

1.02

0.94

9.21

1998

2.26

1.45

0.95

1.43

4.55

0.36

1.06

0.00

1.00

0.04

1.07

1.11

15.28

1999

1.64

2.50

0.59

0.23

0.28

1.02

0.00

0.09

0.00

0.40

0.49

0.73

7.97

2000

2.01

2.14

0.97

0.72

0.28

0.26

0.03

0.06

0.39

1.74

0.38

0.66

9.64

2001

1.15

0.41

1.11

0.70

0.37

0.64

0.32

0.00

0.10

0.68

1.33

1.00

7.78

2002

0.77

0.27

0.49

0.77

0.09

0.60

0.14

0.10

0.36

0.29

0.44

1.86

6.18

2003

1.46

0.48

0.99

1.12

1.52

0.24

0.36

0.11

0.15

0.02

0.86

1.47

8.78

2004

1.82

1.54

0.25

0.98

1.70

0.43

0.13

0.64

0.56

2.03

0.93

0.97

11.98

2005

0.41

0.12

1.66

0.80

2.94

1.02

0.22

0.06

0.14

1.38

1.58

3.92

14.25

10-yr avg

1.69

1.01

0.82

0.90

1.33

0.61

0.49

0.17

0.36

0.72

0.88

1.41

10.38

60-yr avg

1.36

0.96

0.93

0.81

1.05

0.76

0.25

0.38

0.48

0.72

1.15

1.32

10.19

Table 2. Annual snowfall totals at the Malheur Experiment Station, Oregon State University, Ontario, OR, 1991-2005.

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

10-yr avg

62-yr avg

----------------------------------------------------------------- inches -----------------------------------------------------------------

7.5

15.5

36.0

32.0

15.0

14.5

5.8

14.6

13.2

13.8

15.5

11.5

4.5

24.0

13.5

14.0

18.2

Table 3. Monthly air temperature, Malheur Experiment Station, Oregon State University, Ontario, OR, 2005.


Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec


Max

Min

Max

Min

Max

Min

Max

Min

Max

Min

Max

Min

Max

Min

Max

Min

Max

Min

Max

Min

Max

Min

Max

Min


-----------------------------------------------------------------------oF ------------------------------------------------------------------

Highest

50

33

58

34

72

47

79

56

89

57

98

61

100

68

101

67

91

58

82

50

59

41

41

33

Lowest

26

12

36

15

50

24

51

27

56

36

67

38

68

41

77

46

59

34

53

32

28

17

20

-2

2005 avg

37

25

47

25

59

34

64

40

72

47

78

50

93

58

92

57

79

46

65

40

45

29

31

18

10-yr avg

38

25

45

27

57

33

64

38

73

46

82

52

92

59

91

55

81

47

66

37

50

30

39

26

60-yr avg

35

20

43

25

55

31

64

37

74

45

82

52

92

58

90

56

80

46

66

36.5

48

28

37

22

Figure 1. Cumulative growing degree days (50-86°F) over time for selected years compared to 15-year average, Malheur Experiment Station, Oregon State University, Ontario, OR.

Table 4. Monthly total growing degree days (50-86°F), Malheur Experiment Station, Oregon State University, Ontario, OR, 1991-2005.

Year

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Total

1991

0

13

16

124

212

389

776

718

436

194

1

0

2,879

1992

0

13

106

202

482

574

639

704

385

174

4

0

3,283

1993

0

0

23

81

423

358

464

524

408

252

6

0

2,539

1994

0

2

92

189

369

523

794

774

509

144

2

0

3,398

1995

0

29

32

106

293

433

680

588

472

101

3

10

2,747

1996

0

5

53

135

243

446

805

658

364

194

18

2

2,923

1997

4

0

81

117

419

509

661

706

481

157

20

0

3,154

1998

0

2

52

112

68

571

802

749

515

151

16

4

3,042

1999

0

2

43

72

329

459

683

703

416

184

30

0

2,921

2000

0

4

36

194

342

536

751

743

368

133

2

0

3,109

2001

0

0

63

126

401

488

715

761

472

155

27

0

3,208

2002

0

2

32

137

319

562

805

621

437

142

14

2

3,073

2003

0

4

72

112

319

594

846

754

448

281

11

2

3,443

2004

0

0

115

187

311

607

776

680

365

180

4

0

3,225

2005

0

7

59

126

286

419

749

733

383

133

4

0

2,899

19-year avg

0

5

57

152

323

519

730

686

432

173

12

1

3,092

Table 5. Monthly total degree days in the above-ideal (86 -104°F) range, Malheur Experiment Station, Oregon State University, Ontario, OR, 1991-2005.

Year

Apr

May

Jun

Jul

Aug

Sep

Oct

Total

1991

0

0

2

41

36

4

0

83

1992

0

5

20

23

54

2

0

104

1993

0

4

4

2

11

5

0

26

1994

0

2

16

68

54

7

0

147

1995

0

0

4

23

22

7

0

56

1996

0

0

5

54

32

4

0

95

1997

0

4

0

27

31

5

0

67

1998

0

0

0

63

45

14

0

122

1999

0

1

2

21

16

1

0

41

2000

0

0

7

41

43

4

0

95

2001

0

5

7

25

45

4

0

86

2002

0

0

14

54

11

5

0

85

2003

0

5

9

74

36

5

0

130

2004

0

0

18

43

31

2

0

94

2005

0

0

4

43

36

4

0

86

15-yr avg

0

2

8

41

34

6

0

90

Table 6. Wind-run daily totals and monthly totals, Malheur Experiment Station, Oregon State University, Ontario, OR, 2005.

Daily

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec


------------------------------------------- miles -----------------------------------------------

Mean

28

13

59

74

42

43

41

41

41

23

39

24

Max

175

42

181

189

104

112

106

139

144

80

125

100

Min

0

4

8

18

11

14

6

12

13

2

5

0

Annual total

-------------------------------------------- miles ------------------------------------------------

2005

863

358

1,831

2,214

1,295

1,296

1,264

1,276

1,242

724

1,173

754

10-yr average

1,521

1,813

2,375

2,415

2,230

1,897

1,701

1,602

1,524

1,655

1,549

1,756

57-yr average




2,152

1,926

1,568

1,470

1,327

1,255

1,284



Table 7. Pan-evaporation totals, Malheur Experiment Station, Oregon State University, Ontario, OR, 2005.

Totals

April

May

Jun

Jul

Aug

Sep

Oct

Total

Daily

-------------------------------------- inches ---------------------------------------

Mean

0.20

0.22

0.31

0.40

0.36

0.24

0.12


Max

0.44

0.37

0.50

0.61

0.53

0.35

0.23


Min

0.08

0.11

0.08

0.09

0.26

0.13

0.00


Annual

---------------------------------------- inches ------------------------------------

2005

5.73

6.91

9.32

12.49

11.22

7.25

3.68

56.6

10-yr avg

6.08

8.39

9.83

11.48

10.42

7.17

4.38

58.3

56-yr avg

5.64

7.72

8.98

11.17

9.64

6.32

3.29

51.8

Table 8. Total accumulated reference evapotranspiration (ET0) and crop evapotranspiration (ETc) (acre-inches/acre), Malheur Experiment Station, Oregon State University, Ontario, OR, 1992-2005.











Poplar

Year

ETo

Alfalfa (mean)

Winter grain

Spring grain

Sugar beets

Onions

Potatoes

Dry beans

Field corn

1st year

2nd year

3rd year +

1992

53.7

44.4

26.9

27.9

36.1

30.3

28.8

21.3

29.8




1993

51.9

36.4

21.3

22.7

29.3

24.1

22.8

17.9

23.7




1994

57.6

40.6

21.3

22.6

34.5

29.5

28.2

21.1

27.7




1995

49.6

37.1

18.9

22.2

29.0

26.7

23.6

16.7

23.7




1996

52.8

39.8

22.3

24.1

32.9

27.2

26.3

19.5

25.7




1997

55.2

41.5

23.8

25.3

33.4

28.0

26.6

19.7

25.1




1998

55.0

40.7

21.3

23.9

32.4

28.2

26.2

21.0

27.9

23.9

37.1

44.0

1999

58.6

43.9

25.0

26.4

33.7

28.9

26.5

21.7

28.5

24.3

37.8

45.5

2000

58.7

45.5

26.0

25.7

38.3

32.0

29.5

24.1

30.6

24.9

38.9

47.1

2001

57.9

43.8

25.5

27.2

34.8

30.3

27.4

21.4

29.1

23.7

37.0

44.7

2002

58.8

41.7

25.9

28.7

35.2

30.4

27.7

21.9

27.8

23.6

36.7

44.4

2003

54.2

44.1

27.5

31.7

39.1

31.6

31.9

22.4

29.3

24.3

37.9

45.9

2004

52.8

43.5

27.8

30.6

34.3

30.2

27.9

22.1

28.4

23.3

36.3

44.1

2005

53.8

44.5

26.5

27.0

36.0

32.8

30.2

20.0

29.2

24.3

37.8

45.3

Average

55.1

41.8

24.1

26.1

34.1

29.0

27.2

20.8

27.5

24.0

37.4

45.1

mm

1,400.5

1,060.9

612.5

662.4

865.6

737.4

690.5

529.1

698.1

609.6

949.6

1,145.5

Table 9. Monthly soil temperature at 4-inch depth, Malheur Experiment Station, Oregon State University, Ontario, OR, 2005.


Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec


Max

Min

Max

Min

Max

Min

Max

Min

Max

Min

Max

Min

Max

Min

Max

Min

Max

Min

Max

Min

Max

Min

Max

Min


---------------------------------------------------------------------oF ----------------------------------------------------------------

Highest

37

35

42

39

50

45

60

54

70

63

74

69

79

72

79

72

70

64

63

56

49

47

34

33

Lowest

30

26

33

32

42

38

44

40

55

50

62

56

68

61

67

60

57

52

49

40

34

33

26

25

2005 avg

32

31

37

35

46

42

51

46

62

56

68

61

75

67

74

67

65

59

55

51

41

40

30

29

10-yr avg

35

34

38

35

46

41

55

47

64

56

73

63

79

69

77

69

69

63

57

52

44

42

37

35

38-yr avg

33

32

38

34

50

41

61

47

72

58

81

66

88

74

86

73

76

63

60

51

44

39

34

33

Table 10. Last and first frost ([32°F) dates and number of frost-free days, Malheur Experiment Station, Oregon State University, Ontario, OR, 1990-2005.

Year

Date of last frost

Date of first frost

Total frost-free days

Spring

Fall

1990

May 8

Oct 7

152

1991

Apr 30

Oct 4

157

1992

Apr 24

Sep 14

143

1993

Apr 20

Oct 11

174

1994

Apr 15

Oct 6

174

1995

Apr 16

Sep 22

159

1996

May 6

Sep 23

140

1997

May 3

Oct 8

158

1998

Apr 18

Oct 17

182

1999

May 11

Sep 28

140

2000

May 12

Sep 24

135

2001

Apr 29

Oct 10

164

2002

May 8

Oct 12

157

2003

May 19

Oct 11

145

2004

April 16

Oct 24

191

2005

April 15

Oct 6

174

1976-2003 Avg

April 28

October 5

160

Table 11. Record weather events at the Malheur Experiment Station, Oregon State University, Ontario, OR.

Record event

Measurement

Date

------------------------------------------ Since 1943 ------------------------------------------------

Greatest annual precipitation

16.87 inches

1983

Greatest monthly precipitation

4.55 inches

May 1998

Greatest 24-hour precipitation

1.52 inches

Sep 14, 1959

Greatest annual snowfall

40 inches

1955

Greatest 24-hour snowfall

10 inches

Nov 30, 1975

Earliest snowfall

1 inch

Oct 25, 1970

Highest air temperature

110°F

July 22, 2003

Total days with maximum air temp. >100°F

17 days

1971

Lowest air temperature

-26°F

Jan 21 and 22, 1962

Total days with minimum air temp. <0°F

35 days

1985

------------------------------------------ Since 1967 ------------------------------------------------

Lowest soil temperature at 4-inch depth

12°F

Dec 24, 25, and 26, 1990

------------------------------------------ Since 1986 -----------------------------------------------

Highest yearly growing degree days

3,446 degree days

1988

Lowest yearly growing degree days

2,539 degree days

1993

------------------------------------------ Since 1992 ------------------------------------------------

Highest reference evapotranspiration

58.8 inches

2002