Days
to first fall freeze (28o F) by location and date in South Dakota.
Calendar date
MAY
JUNE
JULY
AUG
Avg. fall freeze date
20
30
9
19
29
9
19
29
8
18
28
50% chance
Day of year
or Julian date*
of 28o
F.
LOCATION
140
150
160
170
180
190
200
210
220
230
240
Calendar
Julian
Days to fall
freeze (28o F.)**
Aberdeen
137
127
117
107
97
87
77
67
57
47
37
Oct. 4
277
Alexander
147
137
127
117
107
97
87
77
67
57
47
Oct. 14
287
Armour
143
133
123
113
103
93
83
73
63
53
43
Oct. 10
283
Bison
136
126
116
106
96
86
76
66
56
46
36
Oct. 3
276
Britton
136
126
116
106
96
86
76
66
56
46
36
Oct. 3
276
Brookings
134
124
114
104
94
84
74
64
54
44
34
Oct. 1
274
Castlewood
133
123
113
103
93
83
73
63
53
43
33
Sep. 30
273
Centerville
141
131
121
111
101
91
81
71
61
51
41
Oct. 8
281
Chamberlain
140
130
120
110
100
90
80
70
60
50
40
Oct. 7
280
Clark
140
130
120
110
100
90
80
70
60
50
40
Oct. 7
280
Clear Lake
142
132
122
112
102
92
82
72
62
52
42
Oct. 9
282
DeSmet
144
134
124
114
104
94
84
74
64
54
44
Oct. 11
284
Dupree
136
126
116
106
96
86
76
66
56
46
36
Oct. 3
276
Eureka
138
128
118
108
98
88
78
68
58
48
38
Oct. 5
278
Faulkton
133
123
113
103
93
83
73
63
53
43
33
Sep. 30
273
Flandreau
139
129
119
109
99
89
79
69
59
49
39
Oct. 6
279
Forestburg
140
130
120
110
100
90
80
70
60
50
40
Oct. 7
280
Gettysburg
140
130
120
110
100
90
80
70
60
50
40
Oct. 7
280
Gregory
141
131
121
111
101
91
81
71
61
51
41
Oct. 8
281
Highmore
136
126
116
106
96
86
76
66
56
46
36
Oct. 3
276
Hot Springs
131
121
111
101
91
81
71
61
51
41
31
Sep. 28
271
Howard
137
127
117
107
97
87
77
67
57
47
37
Oct. 4
277
Huron
141
131
121
111
101
91
81
71
61
51
41
Oct. 8
281
Kennebec
136
126
116
106
96
86
76
66
56
46
36
Oct. 3
276
Leola
135
125
115
105
95
85
75
65
55
45
35
Oct. 2
275
Long Valley
137
127
117
107
97
87
77
67
57
47
37
Oct. 4
277
Madison
143
133
123
113
103
93
83
73
63
53
43
Oct. 10
283
Martin
135
125
115
105
95
85
75
65
55
45
35
Oct. 2
275
McIntosh
139
129
119
109
99
89
79
69
59
49
39
Oct. 6
279
Menno
141
131
121
111
101
91
81
71
61
51
41
Oct. 8
281
NOTE: Use calendar dates for reference and Julian
dates for calculations. Dates are
listed in 10-day increments.
*Julian
date = day of year (365 days), for example, May 20 is the 140th day of the
year.
**
Days to fall freeze (28o F.) = Fall freeze date (Julian). - Current calendar date
(Julian)
EXAMPLE: Soybeans at Aberdeen are hailed out. It's July 9th, how many days remain to the
first killing frost?
As
indicated above, today's julian date is 190 and the fall freeze Julian date
is 277 (October 4) at Aberdeen.
Therefore: Days to
fall freeze (28oF.)
= 277 (Julian) - 190 (Julian) = 87 days (see table), on July 9th at
Aberdeen.
Days
to first fall freeze (28o F) by location and date in South Dakota.
Calendar date
MAY
JUNE
JULY
AUG
Avg. fall freeze date
20
30
9
19
29
9
19
29
8
18
28
50% chance
Day of year
or Julian date*
of 28o
F.
LOCATION
140
150
160
170
180
190
200
210
220
230
240
Calendar
Julian
Days to fall
freeze (28o F.)**
Milbank
125
115
105
95
85
75
65
55
45
35
25
Sep. 22
265
Miller
143
133
123
113
103
93
83
73
63
53
43
Oct. 10
284
Mission
146
136
126
116
106
96
86
76
66
56
46
Oct. 13
286
Mitchell
146
136
126
116
106
96
86
76
66
56
46
Oct. 13
286
Mobridge
147
137
127
117
107
97
87
77
67
57
47
Oct. 14
287
Murdo
143
133
123
113
103
93
83
73
63
53
43
Oct. 10
283
Newell
136
126
116
106
96
86
76
66
56
46
36
Oct. 3
276
Oelrichs
134
124
114
104
94
84
74
64
54
44
34
Oct. 1
274
Onida
126
116
106
96
86
76
66
56
46
36
26
Sep. 23
266
Philip
145
135
125
115
105
95
85
75
65
55
45
Oct. 12
285
Pierre
147
137
127
117
107
97
87
77
67
57
47
Oct. 14
287
Pollock
138
128
118
108
98
88
78
68
58
48
38
Oct. 5
278
Rapid City
143
133
123
113
103
93
83
73
63
53
43
Oct. 10
283
Redfield
135
125
115
105
95
85
75
65
55
45
35
Oct. 2
275
Redig
130
120
110
100
90
80
70
60
50
40
30
Sep. 27
270
Sioux Falls
140
130
120
110
100
90
80
70
60
50
40
Oct. 7
280
Sisseton
144
134
124
114
104
94
84
74
64
54
44
Oct. 11
284
Spearfish
144
134
124
114
104
94
84
74
64
54
44
Oct. 11
284
Summit
120
110
100
90
80
70
60
50
40
30
20
Sep. 17
260
Timber Lake
139
129
119
109
99
89
79
69
59
49
39
Oct. 6
279
Vermillion
141
131
121
111
101
91
81
71
61
51
41
Oct. 8
281
Wagner
149
139
129
119
109
99
89
79
69
59
49
Oct. 16
289
Wasta
137
127
117
107
97
87
77
67
57
47
37
Oct. 4
277
Watertown
136
126
116
106
96
86
76
66
56
46
36
Oct. 3
276
Webster
135
125
115
105
95
85
75
65
55
45
35
Oct. 2
275
Winner
147
137
127
117
107
97
87
77
67
57
47
Oct. 14
287
Yankton
149
139
129
119
109
99
89
79
69
59
49
Oct. 16
289
NOTE: Use calendar dates for reference and Julian
dates for calculations. Dates are
listed in 10-day increments.
*Julian
date = day of year (365 days), for example, May 20 is the 140th day of the
year.
**
Days to fall freeze (28o F.) = Fall freeze date (Julian). - Current calendar date
(Julian)
EXAMPLE: Soybeans at Milbank are hailed out. It's July 9th, how many days remain to the
first killing frost?
As
indicated above, today's julian date is 190 and the fall freeze Julian date
is 265 (September 22) at Milbank.
Therefore: Days to
fall freeze (28oF.)
= 265 (Julian) - 190 (Julian) = 75 days (see table), on July 9th at
Milbank.
Sources:
Data
- SD Agricultural Statistics Service.
Calculations for
days to first freeze (28oF.) - R.G. Hall, Extension Agronomist - Crops
Plant Sciences Dept.
South Dakota State University, Brookings, SD 57007.