2008 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 a computer in Boise 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 from links on 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 inches 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.

2008 Weather

The total precipitation for 2008 (7.62 inches) was lower than the 10-year (10.21 inches) and 65-year (10.07 inches) averages (Table 1). Total snowfall for 2008 (26.0 inches) was higher than the 10-year (14.0 inches) and 65-year averages (18.2 inches) (Table 2).

The highest air temperature for 2008 was 100°F on June 30 and July 4 (Table 3). The lowest temperature for the year was -4°F on January 24.

March and April had fewer accumulated growing degree days (50° to 86°F) than the 22-year average (Table 4, Fig. 1). Growing degree days accumulated in March were 22 percent of average, and the lowest since 1991 when records began. Growing degree days accumulated in April were 57 percent of average. May, June, July, and August had total growing degree days close to average. The total number of degree days in the above-optimal range (86°to 104°F) in 2008 was close to the average (Table 5).

Total wind runs for May and June were 28 percent and 19 percent above the 17-year average (Table 6). Total pan-evaporation for May and June was 14 percent and 13 percent higher, respectively, than the 10-year average (Table 7). In 2008, total accumulated reference ET and ETc for all crops except poplar were higher than the 16-year average (Table 8).

The average monthly maximum and minimum 4-inch soil temperatures from January through April were lower than the 10-year average (Table 9). Four-inch soil temperatures for the other months were close to the average.

The last spring frost ([32°F) occurred on May 2, 4 days later than the 32-year-average date of April 28; the first fall frost occurred on October 13, 7 days later than the 32-year-average date of October 6 (Table 10).

No local weather records were broken in 2008, but March had the fewest growing degree days since observations were first recorded in 1991 (Table 11).

References

Wright, J.L. 1982. New evapotranspiration crop coefficients. Journal of Irrigation and Drainage Division, American Society of Civil Engineers 108:57-74.



Table 1. Monthly precipitation at the Malheur Experiment Station, Oregon State University, Ontario, OR, 1991-2008.

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

2006

1.91

0.67

3.33

2.00

0.62

0.45

0.00

0.08

0.55

0.28

1.14

1.76

12.79

2007

0.07

0.95

0.12

0.82

0.47

0.63

0.03

0.15

0.92

0.68

1.07

1.56

7.47

2008

0.50

0.43

0.79

0.14

0.74

0.27

0.43

0.03

1.26

0.44

1.12

1.47

7.62

10-yr avg

1.35

1.05

1.05

0.96

1.28

0.57

0.23

0.13

0.42

0.75

0.93

1.50

10.21

65-yr avg

1.28

0.95

0.96

0.80

1.06

0.80

0.22

0.33

0.45

0.73

1.16

1.33

10.07



Table 2. Annual snowfall totals at the Malheur Experiment Station, Oregon State University, Ontario, OR, 1991-2008.

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

10-yr avg

65-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

12.3

3.8

26.0

14.03

18.22



Table 3. Maximum and minimum air temperatures by month, Malheur Experiment Station, Oregon State University, Ontario, OR, 2008.


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

49

34

52

36

63

37

82

46

96

62

100

70

100

67

99

65

89

55

85

52

66

45

56

38

Lowest

18

-4

34

14

47

21

46

21

54

31

63

41

82

49

75

43

63

39

51

26

35

20

18

2

2008 avg

33

17

42

27

52

30

60

33

74

47

82

53

93

59

91

56

79

46

66

38

51

32

38

20

10-yr avg

38

25

45

27

56

33

64

39

72

46

82

52

94

61

91

57

80

47

66

38

48

30

38

25

65-yr avg

35

20

43

25

55

31

64

37

74

45

82

52

92

58

90

56

79

46

66

36

48

28

37

22






Figure 1. Cumulative growing degree days (50-86°F) over time for years with lowest (1993) and highest (2003) totals compared to 2008 and to 18-year average (1990-2007), 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, 1991-2008.

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

2006

0

4

22

131

364

599

866

668

394

151

31

0

3,230

2007

0

7

99

146

405

551

871

682

398

115

20

0

3,294

2008

0

0

13

86

333

504

774

700

387

144

16

2

2,959

22-year avg

0

6

58

150

327

520

743

687

426

168

13

1

3,099



Table 5. Monthly total degree days in the above-ideal (86-104°F) range, Malheur Experiment Station, Oregon State University, Ontario, OR, 1991-2008.

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

2006

0

5

13

81

23

5

0

128

2007

0

0

14

79

29

5

0

128

2008

0

3.6

9

41.4

30.6

0

0

84.6

18-yr avg

0

2

8

45

33

5

0

94



Table 6. Daily wind-run and monthly totals, Malheur Experiment Station, Oregon State University, Ontario, OR, 2008.

Daily

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec


------------------------------------------- miles/day -----------------------------------------------

Mean

53

65

61

72

89

74

51

45

33

41

25

42

Max.

237

288

165

210

303

212

141

173

193

235

132

155

Min.

2

4

11

16

18

23

17

6

7

3

0

3

Monthly total

-------------------------------------------- miles/month ------------------------------------------------

2008

1,654

1,872

1,878

2,174

2,768

2,213

1,567

1,409

987

1,268

755

1,303

17-yr average

1,457

1,670

2,342

2,412

2,163

1,867

1,688

1,550

1,460

1,601

1,485

1,648

60-yr average




2,165

1,922

1,575

1,478

1,326

1,250

1,287





Table 7. Daily pan-evaporation and monthly totals, Malheur Experiment Station, Oregon State University, Ontario, OR, 2008.

Totals

April

May

Jun

Jul

Aug

Sep

Oct

Total

Daily

-------------------------------------- inches/day ---------------------------------------

Mean

0.22

0.31

0.37

0.41

0.35

0.23

0.13


Max.

0.44

0.50

0.65

0.65

0.55

0.47

0.27


Min.

0.11

0.16

0.08

0.27

0.23

0.07

0.04


Monthly

---------------------------------------- inches/month ------------------------------------

2008

6.07

9.67

11.24

12.83

10.79

6.75

4.06

61.41

10-yr avg

6.18

8.45

9.99

12.10

10.54

7.07

4.32

58.27

60-yr avg

5.66

7.76

9.03

11.26

9.69

6.36

3.33

51.78



Table 8. Total accumulated reference evapotranspiration (ET0) and crop evapotranspiration (ETc) (acre-inches/acre), Malheur Experiment Station, Oregon State University, Ontario, OR, 1992-2008.











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

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

2006

57.7

47.8

24.3

30.2

38.4

32.4

30.9

22.4

29.6

26.2

40.8

49.3

2007

59.0

47.2

27.6

26.7

38.9

33.7

29.7

24.5

30.5

25.7

40.1

48.6

2008

58.0

46.4

28.1

30.4

36.4

32.7

30.0

24.0

30.4

23.3

36.5

44.5

Average

55.5

42.7

24.5

26.5

34.8

29.9

27.7

21.2

28.0

24.4

38.1

45.9

mm

1,409

1,084

622

673

883

758

703

539

710

620

967

1,166



Table 9. Monthly soil temperature at 4-inch depth, Malheur Experiment Station, Oregon State University, Ontario, OR, 2008.


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 ----------------------------------------------------------------

2008 avg

30

29

32

30

42

39

48

43

61

56

69

62

75

70

72

67

64

61

54

51

44

43

35

33

Highest

32

31

40

36

45

42

58

50

70

64

79

73

80

73

78

72

67

69

63

61

51

50

47

45

Lowest

25

21

29

27

38

36

42

37

50

46

60

56

72

67

67

62

61

58

48

44

38

36

29

26

10-yr avg

34

33

36

35

44

41

51

47

61

55

69

62

75

68

73

67

66

61

55

51

43

41

35

34

41-yr avg

33

32

37

34

49

41

60

47

72

58

80

66

88

74

86

73

75

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, 1990-2008.

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

2006

April 19

Oct 22

186

2007

May 4

Oct 11

160

2008

May 2

Oct 13

164

1976-2007 Avg

April 28

Oct 6

161



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

Record event

Measurement

Date

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

Highest annual precipitation

16.87 inches

1983

Lowest annual precipitation

5.16 inches

1949

Highest monthly precipitation

4.55 inches

May 1998

Highest 24-hour precipitation

1.52 inches

Sep 14, 1959

Highest annual snowfall

40 inches

1955

Highest 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. m100°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 1991/1992 ------------------------------------------------

Fewest growing degree days in March

13

2008

Highest reference evapotranspiration

59.0 inches

2007