Idaho Frost Dates

Idaho has 143 NOAA weather stations with freeze records in the 1991–2020 climate normals. The typical last spring frost ranges from April 2 at Brownlee Dam to June 22 at Mccall; at half the stations it has come by May 16. The first fall frost typically arrives between September 2 at Mccall and November 5 at Brownlee Dam, with a median of September 28.

The growing season between the typical frosts runs from 72 days at Mccall to 216 days at Brownlee Dam; 132 days at the median station.

At 17 stations, a freeze is possible in any month.

Every station in Idaho

Typical dates have a 50% chance of a frost after them in spring, and before them in fall; safer dates, 10%. A garden can differ from its nearest station, especially in a valley or on a hillside: see why your garden may differ.

Idaho: freeze (32 °F) dates by NOAA station, 1991–2020 normals
Station	Elevation	Last frost	Safer	First frost	Safer	Season (days)
Aberdeen Exp Stn	4,405 ft	May 21	Jun 13	Sep 20	Sep 2	118
American Falls 6 Ne	4,415 ft	May 14	Jun 4	Oct 2	Sep 16	138
American Falls	4,510 ft	May 4	May 21	Oct 8	Sep 22	155
Arco 17 Sw	5,920 ft	May 24	Jun 15	Oct 1	Sep 16	130
Arco	5,325 ft	May 22	Jun 9	Sep 22	Sep 4	119
Arrowrock Dam	3,235 ft	Apr 28	May 16	Oct 14	Oct 1	169
Ashton 1n	5,212 ft	May 21	Jun 13	Sep 21	Sep 4	121
Bayview Model Basin	2,087 ft	May 22	Jun 6	Sep 22	Sep 3	122
Bellevue	5,192 ft	May 13	Jun 3	Oct 2	Sep 15	139
Bern	5,964 ft	Jun 17	Jul 4	Sep 3	Aug 18	77
Blackfoot Fire Dept	4,499 ft	May 5	May 22	Oct 3	Sep 16	149
Boise 7 N	3,885 ft	May 17	Jun 10	Oct 12	Sep 27	147
Boise Air Terminal	2,814 ft	Apr 24	May 9	Oct 21	Oct 5	179
Boise Lucky Peak Dam	2,840 ft	Apr 30	May 18	Oct 22	Sep 30	173
Bonners Ferry	2,075 ft	Apr 30	May 16	Oct 4	Sep 18	154
Brownlee Dam	1,844 ft	Apr 2	Apr 20	Nov 5	Oct 24	216
Bruneau	2,530 ft	Apr 17	May 7	Oct 17	Oct 1	181
Buhl #2	3,800 ft	Apr 25	May 10	Oct 15	Sep 29	172
Burley Muni Ap	4,142 ft	May 7	May 23	Oct 4	Sep 21	150
Cabinet Gorge	2,173 ft	May 9	May 25	Oct 8	Sep 25	153
Cambridge	2,650 ft	May 15	Jun 4	Sep 27	Sep 12	134
Cascade 1 Nw	4,896 ft	May 30	Jun 21	Sep 19	Sep 3	110
Castleford 2 N	3,825 ft	May 17	Jun 5	Sep 29	Sep 11	132
Challis Ap	5,033 ft	May 14	Jun 2	Sep 25	Sep 10	131
Chilly Barton Flat	6,260 ft	Jun 14	Jun 30	Sep 8	Aug 26	86
Coeur D'Alene	2,133 ft	Apr 22	May 6	Oct 18	Oct 4	179
Cottonwood 2 Wsw	3,945 ft	May 6	May 26	Oct 13	Sep 28	156
Council	2,943 ft	May 10	Jun 1	Oct 2	Sep 16	145
Craters Of The Moon	5,914 ft	Jun 19	Jul 2	Sep 9	Aug 25	81
Deadwood Lodge	5,948 ft	A freeze is possible in any month
Deer Flat Dam	2,510 ft	Apr 23	May 9	Oct 18	Oct 2	178
Dixie N	5,740 ft	A freeze is possible in any month
Dixie	5,620 ft	A freeze is possible in any month
Downey	4,865 ft	May 31	Jun 16	Sep 18	Sep 3	110
Driggs	6,120 ft	Jun 13	Jun 28	Sep 9	Aug 26	86
Dubois Exp Stn	5,450 ft	May 18	Jun 9	Sep 30	Sep 14	132
Dworshak Fish Hatchery	995 ft	Apr 20	May 5	Oct 20	Sep 30	182
Elk City 1ne	4,058 ft	A freeze is possible in any month
Elk Rvr	2,866 ft	May 16	Jun 1	Sep 23	Sep 6	128
Emmett 2 E	2,390 ft	Apr 30	May 17	Oct 17	Oct 2	168
Fairfield Rs	5,065 ft	Jun 8	Jun 28	Sep 14	Aug 29	97
Fenn Rs	1,560 ft	Apr 26	May 9	Oct 20	Oct 1	176
Ft Hall 1 Nne	4,465 ft	May 20	Jun 12	Sep 20	Sep 1	119
Garden Valley	3,100 ft	Jun 1	Jun 20	Sep 10	Aug 28	102
Gibbonsville #2	4,480 ft	Jun 1	Jun 19	Sep 17	Sep 2	107
Glenns Ferry	2,466 ft	May 1	May 16	Oct 3	Sep 16	154
Grace	5,550 ft	May 29	Jun 16	Sep 17	Sep 1	111
Grand View 4 Nw	2,400 ft	Apr 28	May 13	Oct 6	Sep 24	162
Grangeville	3,300 ft	May 9	May 27	Oct 3	Sep 14	146
Hagerman 2 Sw	2,897 ft	May 3	May 17	Oct 1	Sep 16	151
Hamer 4 Nw	4,790 ft	Jun 3	Jun 21	Sep 11	Aug 30	98
Hazelton	4,060 ft	May 7	May 26	Oct 5	Sep 19	149
Headquarters	3,200 ft	A freeze is possible in any month
Hill City 1 W	5,100 ft	Jun 16	Jul 3	Sep 6	Aug 20	80
Homedale 1 Se	2,230 ft	Apr 24	May 5	Oct 9	Sep 26	169
Howe	4,820 ft	May 24	Jun 14	Sep 14	Sep 1	113
Idaho City	3,965 ft	Jun 17	Jul 4	Sep 5	Aug 23	80
Idaho Falls - Kifi	4,742 ft	May 9	Jun 2	Oct 1	Sep 17	142
Idaho Falls 16 Se	5,828 ft	Jun 9	Jun 26	Sep 11	Aug 27	93
Idaho Falls 46 W	4,938 ft	Jun 11	Jul 1	Sep 6	Aug 24	89
Idaho Falls Fanning Fld	4,729 ft	May 23	Jun 13	Sep 20	Sep 1	114
Island Park	6,290 ft	A freeze is possible in any month
Jerome Co Ap	4,048 ft	May 1	May 16	Oct 14	Sep 29	165
Jerome	3,740 ft	May 2	May 30	Oct 14	Sep 30	166
Kamiah	1,210 ft	Apr 29	May 12	Oct 5	Sep 22	163
Kellogg	2,377 ft	May 14	Jun 3	Sep 26	Sep 9	131
Ketchum Rs	5,890 ft	A freeze is possible in any month
Kooskia 5 Sse	2,330 ft	Apr 30	May 13	Oct 11	Sep 19	162
Lava Hot Springs	4,595 ft	May 21	Jun 11	Sep 21	Sep 3	118
Leadore #2	6,000 ft	A freeze is possible in any month
Lewiston Nez Perce Co Ap	1,436 ft	Apr 6	Apr 26	Oct 26	Oct 10	200
Lifton Pumping Stn	5,935 ft	May 19	Jun 5	Sep 21	Sep 5	123
Lowman	3,920 ft	Jun 6	Jul 1	Sep 4	Aug 19	87
Mackay Lost Rvr Rs	5,897 ft	Jun 1	Jun 21	Sep 20	Sep 4	109
Malad City	4,470 ft	May 22	Jun 16	Sep 20	Sep 4	116
Malta 4 Ese	4,590 ft	Jun 1	Jun 19	Sep 19	Sep 2	111
Malta	4,521 ft	Jun 5	Jun 23	Sep 13	Aug 28	96
Massacre Rocks Sp	4,195 ft	May 20	Jun 9	Sep 26	Sep 8	125
May 2sse	5,050 ft	Jun 12	Jun 29	Sep 6	Aug 23	85
Mccall Ap	5,013 ft	Jun 10	Jun 28	Sep 10	Aug 29	93
Mccall	5,025 ft	Jun 22	Jul 10	Sep 2	Aug 14	72
Mccammon	4,770 ft	May 23	Jun 10	Sep 24	Sep 7	121
Middle Fork Lodge	4,480 ft	May 21	Jun 13	Sep 18	Sep 3	115
Minidoka Dam	4,164 ft	May 16	Jun 5	Oct 1	Sep 13	136
Monteview	4,815 ft	Jun 12	Jun 30	Sep 7	Aug 25	87
Moscow U Of I	2,660 ft	A freeze is possible in any month
Mtn Home	3,140 ft	May 2	May 23	Oct 8	Sep 25	157
Mullan Pass Vor/Dme	6,028 ft	Jun 10	Jun 25	Sep 23	Sep 4	104
Mullan	3,201 ft	May 12	Jun 19	Sep 30	Sep 12	138
Murphy (Desert) Hot Springs	5,152 ft	A freeze is possible in any month
Murphy 10 W	3,950 ft	May 17	Jun 6	Sep 30	Sep 14	134
Nampa Sugar Factory	2,470 ft	Apr 29	May 18	Oct 13	Sep 29	164
New Meadows Rs	3,862 ft	A freeze is possible in any month
Nezperce	3,248 ft	May 24	Jun 19	Sep 20	Sep 1	116
Oakley	4,559 ft	May 15	Jun 6	Oct 2	Sep 16	137
Ola	3,075 ft	May 31	Jun 19	Sep 16	Sep 2	108
Parma Exp Stn	2,290 ft	Apr 27	May 9	Oct 9	Sep 26	165
Paul 1ene	4,150 ft	May 6	May 22	Oct 6	Sep 22	151
Payette	2,150 ft	Apr 19	May 5	Oct 20	Oct 6	183
Picabo	4,839 ft	Jun 16	Jun 30	Sep 9	Aug 25	85
Pierce	3,080 ft	Jun 3	Jun 29	Sep 7	Aug 22	93
Plummer 3 Wsw	2,905 ft	May 11	Jun 4	Oct 5	Sep 15	143
Pocatello 2 Ne	4,832 ft	May 16	Jun 6	Oct 2	Sep 14	137
Pocatello City	4,460 ft	May 2	May 18	Oct 11	Sep 26	161
Pocatello Rgnl Ap	4,478 ft	May 23	Jun 13	Sep 18	Sep 3	117
Porthill 1 Sw	1,799 ft	May 4	May 28	Sep 30	Sep 10	145
Potlatch 3 Nne	2,760 ft	May 15	Jun 2	Sep 21	Aug 31	126
Powell	3,530 ft	May 31	Jun 26	Sep 12	Aug 28	102
Preston	4,719 ft	May 16	Jun 4	Sep 28	Sep 14	133
Prichard 3 Ese	2,547 ft	May 31	Jun 23	Sep 5	Aug 20	95
Priest Rvr Exp Stn	2,371 ft	May 20	Jun 4	Sep 13	Sep 1	114
Red River Rs	4,350 ft	A freeze is possible in any month
Rexburg Byu Idaho	5,005 ft	May 12	Jun 2	Sep 24	Sep 6	132
Rexburg Madison Co Ap	4,858 ft	May 15	Jun 3	Sep 23	Sep 8	129
Reynolds	3,930 ft	May 21	Jun 12	Sep 28	Sep 13	126
Richfield	4,309 ft	May 24	Jun 14	Sep 26	Sep 10	123
Rigby	4,856 ft	May 9	May 25	Oct 5	Sep 21	148
Riggins	2,056 ft	May 6	May 26	Oct 9	Sep 24	155
Saint Anthony	4,910 ft	May 17	Jun 10	Sep 22	Sep 5	126
Saint Maries	2,151 ft	May 3	May 18	Oct 4	Sep 18	152
Salmon-Ksra	3,953 ft	May 17	Jun 9	Sep 24	Sep 9	127
Sandpoint Exp Stn	2,126 ft	May 8	May 25	Sep 28	Sep 11	141
Shoshone 1 Wnw	3,950 ft	Apr 24	May 12	Oct 16	Oct 2	173
Shoup	3,400 ft	May 3	May 21	Oct 8	Sep 24	157
Silver City 5 W	6,160 ft	May 31	Jun 17	Oct 6	Sep 10	128
Small 6n	5,740 ft	Jun 5	Jun 21	Sep 20	Sep 3	106
Soda Springs Ap	5,842 ft	A freeze is possible in any month
Stanley Rs	6,495 ft	A freeze is possible in any month
Stanley	6,249 ft	A freeze is possible in any month
Sugar City	4,925 ft	May 29	Jun 18	Sep 13	Aug 30	106
Swan Falls Ph	2,325 ft	Apr 12	May 6	Oct 26	Oct 9	193
Swan Valley	5,397 ft	A freeze is possible in any month
Taylor Rch	3,835 ft	May 11	Jun 1	Sep 30	Sep 15	140
Tetonia Exp Stn	6,170 ft	Jun 15	Jun 29	Sep 7	Aug 24	85
Twin Falls 6 E	3,960 ft	May 6	May 26	Oct 3	Sep 16	150
Twin Falls Sun Vly Rgnl Ap	4,151 ft	May 9	May 28	Oct 4	Sep 20	147
Twin Falls-Kmvt	3,670 ft	Apr 30	May 14	Oct 9	Sep 24	161
Wallace	2,710 ft	May 5	May 21	Oct 2	Sep 17	149
Warren	5,907 ft	A freeze is possible in any month
Weiser	2,120 ft	Apr 23	May 10	Oct 13	Oct 1	174
Winchester	3,972 ft	May 23	Jun 19	Sep 25	Sep 7	121
Yellowpine Bar	2,480 ft	May 2	May 14	Oct 10	Sep 26	159
Yellowpine	5,050 ft	Jun 12	Jul 5	Sep 11	Aug 26	88

Plan your garden with these dates

Enter your ZIP code in the planner: it picks the nearest of these stations and dates every crop in your beds from its frosts. Free, in your browser.

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Questions

When is the last frost in Idaho?

It depends on where you are. The typical last spring frost at Idaho's NOAA stations ranges from April 2 to June 22, and half of them have had it by May 16. Enter your ZIP code above for the station nearest you.

When is the first frost in Idaho?

Typically between September 2 and November 5, depending on the station; the median is September 28. Plan fall crops back from your own station's date.

What do "typical" and "safer" mean?

With the typical (50%) last-frost date, half of years still have a frost after it. With the safer (10%) date, only one year in ten does. In fall it's the other way around: the safer date is the earlier one.

Sources

NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020 (annual/seasonal, by station: freeze dates at 32 °F)

Idaho Frost Dates

Every station in Idaho

Plan your garden with these dates

Questions

Other states

Sources