1999 Weather Summaries
Central Agricultural Research Center


Table 3. Summary of precipitation and snowfall.
               Central Agricultural Research Center, Moccasin, Montana.   1999
.

 

               Precipitation

            Yearly Snowfall

          Winter Snowfall*

Snow**

Month

1999

91 Yr. Avg.

1999

38 Yr. Avg.

1998-99

37 Yr. Avg.

Depth

 

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

January

0.47

0.58

14.0

12.4

14.0

12.4

7.5

February

0.24

0.46

4.7

6.9

4.7

7.0

3.0

March

0.59

0.75

8.5

11.0

8.5

11.1

4.0

April

1.24

1.15

7.7

8.2

7.7

8.5

4.5

May

1.87

2.56

2.0

1.7

2.0

1.7

 

June

1.80

3.19

 

 

 

 

 

July

1.67

1.72

 

 

 

 

 

August

3.55

1.61

 

 

 

 

 

September

1.29

1.40

0.5

0.8

   

0.8

0.5

October

0.26

0.87

2.0

4.4

   

4.5

1.0

November

0.52

0.59

2.0

7.3

7.6

7.4

1.5

December

0.11

0.56

4.0

10.4

9.0

10.6

2.5

Totals

13.61

15.44

45.4

63.1

53.5

64.0

 

 * Winter Snowfall – Sept. 1998 thru May 1999
** Highest snow depth on the ground during the month.

 

Table 4.  Summary of air temperature and wind velocity.
               Central Agricultural Research Center, Moccasin, Montana.  1999

 

1999 Air Temp. oF

1911-1999 Air Temp oF

Wind Speed  MPH*

Month

Max

Min

Mean

Max

Min

Mean

1999

1910-1999

 

 

 

 

 

 

 

 

 

January

37

17

27.1

32.6

9.2

21.1

6.7

6.0

February

44

24

34.0

36.1

13.0

24.5

7.5

6.0

March

51

26

38.3

40.9

19.0

30.1

5.9

6.0

April

50

28

38.9

52.7

29.3

40.9

5.6

6.4

May

60

38

49.1

62.5

38.1

50.3

4.1

5.6

June

71

45

57.6

70.2

45.7

58.0

3.5

4.6

July

79

48

63.0

80.1

50.9

65.5

3.6

4.2

August

81

54

67.4

79.5

49.5

64.5

2.9

4.4

September

66

40

53.0

68.0

40.8

54.5

3.4

4.8

October

60

36

47.7

57.3

32.0

44.6

6.0

4.9

November

56

31

43.7

44.0

21.0

32.6

5.7

5.5

December

45

26

35.4

36.0

13.6

24.8

6.4

6.0

* Wind speed average of 24 hours per day.

Number of days 90 F or above in 1999

June

July

Aug

Sept

Total

89 Yr. Avg.

0

6

4

0

10

10

Number of days 0 F or under in 1999

Jan

Feb

Mar

Apr

Oct

Nov

Dec

Total

89 Yr.Avg.

3

0

0

0

0

0

0

3

27

Lowest temperature recorded in 1999: -14 oF, January 24, 1999
Highest temperature recorded in 1999: 99 oF, July 29, 1999    
Date of highest wind speed in 1999: 15.0 MPH, December 19, 1999

 

Table 5.  Summary of soil temperature at three soil depths under bare ground and sod.
               Central Agricultural Research Center, Moccasin, Montana.  1999

 

4 “ Soil Depth

8 “ Soil Depth

20 “ Soil Depth

4 “ Soil Depth

 

Bare Ground

Bare Ground

Bare Ground

Under Sod

 

1999

34 Yr.

1999

34 Yr.

1999

24 Yr.

1999

34 Yr.

 

Mean

Mean

Mean

Mean

Mean

Mean

Mean

Mean

 

 

 

 

 

 

 

 

 

January

32.7

30.8

34.7

31.1

36.0

34.0

34.6

32.1

February

31.9

32.2

33.4

31.8

35.0

33.1

34.3

32.5

March

39.9

37.1

38.4

35.6

37.0

34.9

39.8

37.9

April

44.8

45.8

44.2

43.7

42.0

40.6

46.8

47.1

May

55.6

56.7

53.0

54.1

48.0

48.6

55.1

57.5

June

66.2

66.7

63.6

63.7

56.0

56.2

65.4

66.6

July

72.3

74.2

69.2

71.1

61.0

62.0

70.0

73.0

August

73.6

72.8

71.0

70.3

64.0

63.5

71.5

72.1

September

59.3

61.3

59.0

60.0

58.0

58.5

59.3

61.7

October

48.5

48.2

48.6

48.1

50.0

50.6

49.9

50.0

November

42.1

37.5

43.2

38.4

46.0

42.9

44.5

40.5

December

33.0

33.0

35.2

33.7

40.0

37.5

35.7

34.8

 

Low and high soil temperature during winter (1998-99) and summer 1999

 

Low (oF)

 

High (oF)

 

4 inch bare

25

Jan. 24   

102

Aug. 3

8 inch bare

33

Jan., Feb., & Mar.

82

July 29

20 inch bare

35

Jan., Feb., & Mar.

65

July 29-31 and numerous days in Aug.

4 inch sod

32

Dec. 25, 30 & Feb. 14-15

82

July 28-29, Aug. 3 & 11

 

Dates soil first froze (32 oF) and dates last thawed 3 days (33 oF) winter 1998-99.

 

Froze

Thawed

4 inch bare

Dec. 21

March 7

8 inch bare

 Did not freeze

     

20 inch bare

Did not freeze

 

4 inch sod

Dec. 25

Feb. 16

 

Table 6.  Inches of evaporation from a free water surface.
               Central Agricultural Research Center, Moccasin, Montana.   1999
.

 

Water Evap. – inches

Precipitation – inches

Month

1999

1909-99

1999

1909-99

 

 

 

 

 

April

2.90

4.10

1.24

1.15

May

3.51

5.93

1.87

2.56

June

7.54

6.72

1.80

3.19

July

         12.29

8.90

1.67

1.72

August

9.16

8.50

3.55

1.61

September

5.95

5.60

1.29

1.40

Ratio of Precipitation to Evaporation

             1999:               1 inch precipitation to 3.62” evaporation
             1909-1999:      1 inch precipitation to 3.70” evaporation
 

Highest daily evaporation in 1999:  0.85” on  August 19, 1999

Table 7.  Summary of growing degree units.
               Central Agricultural Research Center, Moccasin, Montana.   1999
.  

 

GDU*

Mean Air Temp oF

Month

1999

1911-99

1999

1911-99

 

 

 

 

 

May

178

207

49.1

50.1

June

316

313

57.6

57.9

July

438

490

63.0

65.4

August

536

475

67.4

64.6

September

254

286

53.0

54.5

October

177

161

47.7

44.8

Total

1899

1932

 

 

         

*GDU = (max. temp. + min. temp.)/2 – 50
               If max. temp. > 86, substitute it with 86
               If min. temp. < 50, substitute it with 50

The 50-86 degree temperature range is considered the optimum growth range for corn.  Temperatures above or below these limits can slow development and growth.  GDU is used as a method of rating plant maturity.  The more heat units, the faster plants will grow.  Some research has shown that a 40-90 degree temperature range is more normal for most small grains.  GDU is figured on a daily basis and added to previous days’ totals.