| Station |
County |
Temp
Threshold
(Deg. F) |
Spring (Date)
Probability Level |
Fall (Date)
Probability Level |
Freeze Free Period
Probability Level |
| 90 |
50 |
10 |
10 |
50 |
90 |
10 |
50 |
90 |
| Belgrade AP |
Gallatin |
36
32
28 |
May 29
May 09
Apr 24 |
Jun 20
Jun 03
May 09 |
Jul 12
Jun 27
May 24 |
Aug 20
Aug 28
Sep 08 |
Sep 04
Sep 12
Sep 23 |
Sep 19
Sep 27
Oct 09 |
102
133
159 |
75
101
137 |
48
69
114 |
| Big Sandy |
Chouteau |
36
32
28 |
May 21
May 07
Apr 22 |
Jun 08
May 25
May 09 |
Jun 26
Jun 12
May 25 |
Aug 19
Sep 01
Sep 09 |
Sep 04
Sep 14
Sep 24 |
Sep 19
Sep 28
Oct 09 |
113
133
157 |
87
112
138 |
61
90
119 |
| Big Timber |
Sweet
Grass |
36
32
28 |
May 15
May 02
Apr 19 |
Jun 05
May 18
May 01 |
Jun 26
Jun 03
May 12 |
Aug 25
Sep 04
Sep 15 |
Sep 09
Sep 20
Oct 02 |
Sep 24
Oct 06
Oct 20 |
125
149
175 |
95
124
154 |
65
99
132 |
| Bigfork 13 S |
Flathead |
36
32
28 |
May 16
Apr 30
Apr 05 |
Jun 02
May 16
Apr 24 |
Jun 19
May 31
May 12 |
Aug 29
Sep 11
Sep 22 |
Sep 17
Sep 29
Oct 14 |
Oct 06
Oct 17
Nov 06 |
134
159
205 |
106
136
173 |
78
113
141 |
Billings
Water Plant |
Yellowstone |
36
32
28 |
May 11
Apr 25
Apr 18 |
May 26
May 12
Apr 30 |
Jun 10
May 29
May 12 |
Sep 01
Sep 06
Sep 18 |
Sep 14
Sep 23
Oct 04 |
Sep 28
Oct 10
Oct 21 |
133
156
178 |
111
133
157 |
89
110
135 |
| Bridger |
Carbon |
36
32
28 |
May 12
Apr 27
Apr 17 |
Jun 05
May 16
May 02 |
Jun 28
Jun 04
May 17 |
Aug 27
Sep 06
Sep 18 |
Sep 10
Sep 20
Oct 03 |
Sep 23
Oct 05
Oct 18 |
125
151
173 |
97
127
153 |
68
102
134 |
| Broadus |
Powder
River |
36
32
28 |
May 10
May 01
Apr 20 |
May 31
May 19
May 06 |
Jun 22
Jun 07
May 21 |
Aug 20
Aug 31
Sep 10 |
Sep 05
Sep 14
Sep 24 |
Sep 21
Sep 28
Oct 08 |
123
140
158 |
96
117
140 |
69
94
122 |
| Chester |
Liberty |
36
32
28 |
May 30
May 17
Apr 29 |
Jun 23
Jun 06
May 15 |
Jul 17
Jun 26
Jun 01 |
Aug 12
Aug 27
Sep 03 |
Aug 27
Sep 08
Sep 17 |
Sep 12
Sep 21
Oct 01 |
92
118
145 |
64
94
124 |
37
70
103 |
| Chinook |
Blaine |
36
32
28 |
May 16
May 03
Apr 18 |
Jun 02
May 16
May 04 |
Jun 19
May 29
May 20 |
Aug 22
Sep 03
Sep 09 |
Sep 06
Sep 16
Sep 23 |
Sep 22
Sep 29
Oct 08 |
116
140
162 |
96
122
142 |
77
104
122 |
Conrad
Airport |
Pondera |
36
32
28 |
May 30
May 12
Apr 30 |
Jun 19
May 27
May 13 |
July 09
Jun 12
May 25 |
Aug 17
Aug 28
Sep 07 |
Sep 02
Sep 14
Sep 23 |
Sep 19
Sep 30
Oct 09 |
103
133
151 |
75
109
132 |
47
84
113 |
| Culbertson |
Roosevelt |
36
32
28 |
May 20
May 06
Apr 26 |
Jun 08
May 22
May 14 |
Jun 27
Jun 07
May 31 |
Aug 10
Aug 27
Sep 06 |
Aug 28
Sep 10
Sep 19 |
Sep 15
Sep 25
Oct 01 |
107
134
149 |
80
110
128 |
53
87
106 |
Dillon
WMCE |
Beaverhead |
36
32
28 |
Jun 11
May 17
May 02 |
Jun 30
Jun 08
May 18 |
Jul 18
Jun 30
Jun 03 |
Aug 15
Aug 25
Sep 03 |
Aug 27
Sep 07
Sep 18 |
Sep 09
Sep 20
Oct 03 |
82
115
142 |
58
91
122 |
34
67
103 |
| Ekalaka |
Carter |
36
32
28 |
May 17
May 11
Apr 19 |
Jun 07
May 26
May 09 |
Jun 27
Jun 10
May 29 |
Aug 17
Aug 30
Sep 07 |
Sep 03
Sep 15
Sep 25 |
Sep 19
Oct 01
Oct 13 |
113
133
160 |
87
112
138 |
61
90
115 |
| Fairfield |
Teton |
36
32
28 |
May 23
May 07
Apr 23 |
Jun 09
May 20
May 06 |
Jun 26
Jun 03
May 19 |
Aug 28
Sep 04
Sep 15 |
Sep 09
Sep 20
Oct 03 |
Sep 21
Oct 07
Oct 21 |
111
146
172 |
91
122
149 |
71
99
126 |
| Fort Benton |
Chouteau |
36
32
28 |
May 17
May 09
Apr 24 |
Jun 08
May 21
May 07 |
Jun 29
Jun 03
May 20 |
Aug 26
Sep 02
Sep 08 |
Sep 07
Sep 14
Sep 24 |
Sep 20
Sep 25
Oct 10 |
114
132
160 |
91
114
139 |
68
97
119 |
| Geraldine |
Chouteau |
36
32
28 |
May 23
May 06
Apr 28 |
Jun 17
May 24
May 10 |
Jul 12
Jun 11
May 22 |
Aug 19
Sep 03
Sep 06 |
Sep 03
Sep 14
Sep 23 |
Sep 19
Sep 24
Oct 09 |
111
133
154 |
78
112
135 |
45
90
117 |
| Glendive |
Dawson |
36
32
28 |
May 01
Apr 21
Apr 14 |
May 14
May 05
Apr 27 |
May 28
May 19
May 09 |
Sep 04
Sep 10
Sep 21 |
Sep 18
Sep 27
Oct 06 |
Oct 02
Oct 14
Oct 21 |
144
168
181 |
126
145
162 |
107
121
142 |
| Hamilton |
Ravalli |
36
32
28 |
May 20
May 06
Apr 19 |
Jun 07
May 24
May 04 |
Jun 25
Jun 12
May 19 |
Aug 25
Sep 06
Sep 17 |
Sep 05
Sep 20
Oct 03 |
Sep 16
Oct 03
Oct 20 |
110
143
175 |
89
117
152 |
68
92
128 |
| Hardin |
Big Horn |
36
32
28 |
May 09
Apr 27
Apr 17 |
May 31
May 17
May 01 |
Jun 22
Jun 05
May 14 |
Aug 27
Sep 06
Sep 15 |
Sep 09
Sep 20
Oct 01 |
Sep 23
Oct 05
Oct 17 |
125
149
170 |
100
126
153 |
76
103
135 |
| Harlem |
Blaine |
36
32
28 |
May 17
May 06
Apr 23 |
Jun 05
May 23
May 08 |
Jun 24
Jun 08
May 24 |
Aug 18
Sep 02
Sep 09 |
Sep 04
Sep 15
Sep 24 |
Sep 22
Sep 28
Oct 08 |
119
137
157 |
91
114
138 |
63
91
118 |
| Harlowton |
Wheatland |
36
32
28 |
May 27
May 08
Apr 27 |
Jun 18
May 27
May 15 |
Jul 10
Jun 15
Jun 03 |
Aug 17
Aug 29
Sep 06 |
Aug 29
Sep 11
Sep 22 |
Sep 10
Sep 24
Oct 07 |
98
131
151 |
72
106
129 |
45
81
106 |
Helena
WSO |
Lewis &
Clark |
36
32
28 |
May 16
May 02
Apr 16 |
Jun 04
May 18
May 02 |
Jun 23
Jun 02
May 18 |
Aug 25
Sep 02
Sep 13 |
Sep 08
Sep 18
Sep 29 |
Sep 21
Oct 03
Oct 16 |
120
141
172 |
95
122
149 |
70
104
126 |
| Hysham |
Treasure |
36
32
28 |
May 12
Apr 29
Apr 16 |
May 28
May 16
Apr 30 |
Jun 13
Jun 01
May 14 |
Aug 28
Sep 04
Sep 15 |
Sep 09
Sep 18
Oct 02 |
Sep 21
Oct 02
Oct 18 |
122
143
173 |
103
124
154 |
84
106
135 |
| Jordan |
Garfield |
36
32
28 |
May 17
May 03
Apr 23 |
Jun 04
May 19
May 05 |
Jun 23
Jun 03
May 17 |
Aug 18
Aug 31
Sep 08 |
Sep 03
Sep 14
Sep 23 |
Sep 19
Sep 27
Oct 09 |
115
136
157 |
90
117
140 |
65
99
124 |
| Kalispell |
Flathead |
36
32
28 |
May 20
Apr 30
Apr 11 |
Jun 12
May 20
Apr 28 |
Jul 05
Jun 10
May 15 |
Aug 26
Sep 07
Sep 15 |
Sep 07
Sep 20
Oct 02 |
Sep 19
Oct 03
Oct 19 |
116
148
183 |
87
122
157 |
57
96
130 |
Lewistown
FAA AP |
Fergus |
36
32
28 |
May 22
May 10
Apr 25 |
Jun 15
May 24
May 10 |
Jul 10
Jun 07
May 26 |
Aug 20
Sep 01
Sep 09 |
Sep 03
Sep 18
Sep 25 |
Sep 17
Oct 04
Oct 12 |
106
137
156 |
79
116
137 |
51
94
118 |
Medicine
Lake 3 SE |
Sheridan |
36
32
28 |
May 09
May 02
Apr 23 |
May 28
May 18
May 11 |
Jun 16
Jun 03
May 29 |
Aug 18
Sep 01
Sep 07 |
Sep 05
Sep 18
Sep 24 |
Sep 23
Oct 05
Oct 11 |
124
148
160 |
99
123
136 |
74
98
111 |
Miles City
FAA AP |
Custer |
36
32
28 |
Apr 30
Apr 22
Apr 11 |
May 16
May 07
Apr 25 |
Jun 01
May 22
May 09 |
Sep 05
Sep 13
Sep 27 |
Sep 21
Sep 29
Oct 12 |
Oct 08
Oct 15
Oct 27 |
148
167
189 |
128
145
169 |
107
122
149 |
| Plevna |
Fallon |
36
32
28 |
May 15
May 05
Apr 25 |
Jun 04
May 21
May 09 |
Jun 24
Jun 06
May 23 |
Aug 18
Aug 26
Sep 07 |
Sep 03
Sep 14
Sep 24 |
Sep 18
Oct 03
Oct 12 |
113
141
158 |
90
116
137 |
67
90
117 |
| Poplar |
Roosevelt |
36
32
28 |
May 07
May 01
Apr 20 |
May 24
May 15
May 04 |
Jun 10
May 29
May 19 |
Aug 31
Sep 07
Sep 11 |
Sep 12
Sep 20
Sep 27 |
Sep 25
Oct 03
Oct 13 |
132
146
165 |
110
127
145 |
89
108
125 |
| Roundup |
Musselshell |
36
32
28 |
May 12
Apr 28
Apr 18 |
May 29
May 14
May 02 |
Jun 15
May 30
May 15 |
Aug 30
Sep 01
Sep 14 |
Sep 10
Sep 17
Sep 29 |
Sep 21
Oct 03
Oct 14 |
123
144
167 |
103
125
150 |
84
106
133 |
| Scobey |
Daniels |
36
32
28 |
May 12
May 02
Apr 20 |
May 29
May 18
May 07 |
Jun 14
Jun 03
May 24 |
Aug 18
Aug 29
Sep 06 |
Sep 06
Sep 15
Sep 26 |
Sep 26
Oct 01
Oct 15 |
124
141
167 |
100
119
140 |
76
98
114 |
| Sidney |
Richland |
36
32
28 |
May 10
May 04
Apr 22 |
May 31
May 17
May 07 |
Jun 21
May 29
May 21 |
Aug 26
Sep 06
Sep 12 |
Sep 08
Sep 19
Sep 26 |
Sep 22
Oct 01
Oct 09 |
122
142
159 |
99
125
141 |
76
107
124 |
Stanford 1
WNW |
Judith
Basin |
36
32
28 |
Jun 02
May 16
May 01 |
Jun 24
Jun 03
May 15 |
Jul 16
Jun 20
May 29 |
Aug 18
Aug 28
Sep 08 |
Aug 30
Sep 11
Sep 23 |
Sep 12
Sep 24
Oct 08 |
92
122
151 |
66
99
130 |
40
76
109 |
| Terry |
Prairie |
36
32
28 |
May 09
Apr 30
Apr 19 |
May 26
May 14
May 03 |
Jun 12
May 28
May 17 |
Aug 24
Sep 06
Sep 09 |
Sep 09
Sep 18
Sep 26 |
Sep 25
Sep 30
Oct 13 |
125
143
170 |
105
126
146 |
85
109
122 |
Thompson
Falls PH |
Sanders |
36
32
28 |
May 17
May 01
Apr 19 |
Jun 08
May 16
May 04 |
Jun 30
Jun 01
May 19 |
Aug 29
Sep 07
Sep 17 |
Sep 11
Sep 24
Oct 07 |
Sep 25
Oct 10
Oct 27 |
121
154
181 |
94
130
156 |
67
105
131 |
| Townsend |
Broadwater |
36
32
28 |
May 26
May 12
Apr 25 |
Jun 17
May 28
May 10 |
Jul 09
Jun 12
May 24 |
Aug 21
Aug 27
Sep 07 |
Sep 03
Sep 11
Sep 24 |
Sep 15
Sep 26
Oct 11 |
101
128
161 |
77
106
137 |
53
84
112 |
| Vida |
McCone |
36
32
28 |
May 08
Apr 28
Apr 16 |
May 21
May 14
May 03 |
Jun 04
May 30
May 19 |
Aug 28
Sep 05
Sep 15 |
Sep 12
Sep 20
Oct 01 |
Sep 27
Oct 05
Oct 17 |
135
149
170 |
113
129
151 |
91
108
131 |
| Westby |
Sheridan |
36
32
28 |
May 12
May 01
Apr 23 |
May 27
May 17
May 07 |
Jun 12
Jun 02
May 21 |
Aug 18
Sep 04
Sep 09 |
Sep 05
Sep 18
Sep 25 |
Sep 23
Oct 02
Oct 12 |
126
147
160 |
100
123
141 |
74
99
122 |
| Wibaux |
Wibaux |
36
32
28 |
May 23
May 05
Apr 25 |
Jun 17
May 23
May 12 |
Jul 11
Jun 09
May 29 |
Aug 12
Aug 21
Sep 06 |
Aug 28
Sep 08
Sep 23 |
Sep 12
Sep 26
Oct 10 |
100
134
157 |
72
108
133 |
43
81
108 |
| 1/ This
table gives the probability of a later date in the spring and an
earlier date in the fall of the occurrence of temperatures as cold,
or colder, than 36, 32, and 28 degrees Fahrenheit and the probable
length of the freeze-free period relative the same temperature threshold. |
|
