Frost dates / By state
Frost dates in Alaska
NOAA 1991–2020 normals for a 32 °F freeze. Your own yard can run a little either side.
Short answer
Across 55 NOAA weather stations in Alaska, the average last spring frost runs from April 4 at Annette Island Airport to June 10 at Kivalina Airport. The first fall frost comes as early as August 21 at Gulkana Airport and as late as November 1 at Sitka Airport. At 9 of the 64 stations, a freeze can come in any month. Planting zones near these stations run from 1b to 8a.
Alaska cities
- Frost dates in Anchorage: last frost May 1, first frost September 29
Find yours by ZIP code
The table below is by weather station. For the station nearest you, and your planting zone, type your ZIP code.
Alaska frost dates by weather station
| Station | Last spring frost | First fall frost | Frost-free | Zone nearby |
|---|---|---|---|---|
| Anchorage Intl Airport 120 ft | May 5 1 in 10 after May 15 | October 1 1 in 10 by September 18 | 149 days | 5b |
| Anchorage Lake Hood Airport 90 ft | May 1 1 in 10 after May 8 | October 3 1 in 10 by September 22 | 155 days | 5b |
| Anchorage Merrill Fld 138 ft | May 1 1 in 10 after May 9 | September 29 1 in 10 by September 17 | 151 days | 5a |
| Annette Island Airport 109 ft | April 4 1 in 10 after April 22 | October 31 1 in 10 by October 15 | 210 days | 8a |
| Barrow Post Rogers Airport 31 ft | A freeze is possible in any month | 2b | ||
| Bethel Airport 102 ft | May 21 1 in 10 after June 2 | September 22 1 in 10 by September 7 | 124 days | 4a |
| Bettles Airport 642 ft | May 22 1 in 10 after June 5 | August 24 1 in 10 by August 10 | 94 days | – |
| Big Delta Airport 1,277 ft | May 17 1 in 10 after May 31 | September 7 1 in 10 by August 23 | 113 days | – |
| Cold Bay Airport 78 ft | May 25 1 in 10 after June 10 | October 4 1 in 10 by September 20 | 132 days | 7a |
| Cordova M K Smith Airport 31 ft | May 23 1 in 10 after June 5 | September 19 1 in 10 by September 5 | 119 days | – |
| Deadhorse Airport 61 ft | A freeze is possible in any month | – | ||
| Deering Airport 21 ft | A freeze is possible in any month | 3a | ||
| Denali 27 N 2,225 ft | May 25 1 in 10 after June 3 | September 8 1 in 10 by August 26 | 106 days | – |
| Eagle Airport 908 ft | A freeze is possible in any month | – | ||
| Fairbanks 11 NE 1,140 ft | May 12 1 in 10 after May 29 | September 16 1 in 10 by August 29 | 127 days | – |
| Fairbanks Intl Airport 432 ft | May 13 1 in 10 after May 26 | September 13 1 in 10 by August 29 | 123 days | 2b |
| Glennallen 64 N 2,669 ft | June 5 1 in 10 after June 21 | August 24 1 in 10 by August 10 | 80 days | – |
| Gulkana Airport 1,562 ft | June 7 1 in 10 after July 5 | August 21 1 in 10 by August 8 | 75 days | – |
| Gustavus 40 ft | May 30 1 in 10 after June 22 | September 16 1 in 10 by August 29 | 109 days | 7a |
| Gustavus 2 NE 20 ft | May 28 1 in 10 after June 12 | September 25 1 in 10 by August 29 | 120 days | 7a |
| Haines Airport 15 ft | April 25 1 in 10 after May 7 | October 12 1 in 10 by September 30 | 170 days | – |
| Homer Airport 64 ft | May 10 1 in 10 after May 23 | September 29 1 in 10 by September 14 | 142 days | – |
| Iliamna Airport 143 ft | May 10 1 in 10 after May 25 | October 1 1 in 10 by September 17 | 144 days | 4b |
| Juneau Intl Airport 16 ft | May 4 1 in 10 after May 18 | October 3 1 in 10 by September 18 | 152 days | 7a |
| Kaltag Airport 181 ft | May 25 1 in 10 after June 11 | September 3 1 in 10 by August 18 | 101 days | 2a |
| Kenai 29 ENE 282 ft | June 1 1 in 10 after June 18 | September 8 1 in 10 by August 21 | 99 days | – |
| Kenai Muni Airport 91 ft | May 24 1 in 10 after June 4 | September 12 1 in 10 by August 29 | 111 days | – |
| Ketchikan Intl Airport 76 ft | April 22 1 in 10 after May 9 | October 23 1 in 10 by October 3 | 184 days | – |
| King Salmon 63 ft | May 26 1 in 10 after June 11 | September 15 1 in 10 by August 31 | 112 days | – |
| King Salmon 42 SE 661 ft | June 9 1 in 10 after June 22 | September 11 1 in 10 by August 26 | 94 days | – |
| Kivalina Airport 10 ft | June 10 1 in 10 after June 23 | September 11 1 in 10 by August 26 | 93 days | 3a |
| Klawock Airport 12 ft | April 29 1 in 10 after May 14 | October 16 1 in 10 by October 1 | 170 days | 7b |
| Kodiak Airport 80 ft | May 5 1 in 10 after May 21 | October 3 1 in 10 by September 22 | 151 days | – |
| Kotzebue Ralph Wein Airport 30 ft | June 5 1 in 10 after June 17 | September 24 1 in 10 by September 7 | 111 days | – |
| Mcgrath Airport 333 ft | May 13 1 in 10 after May 28 | September 13 1 in 10 by August 27 | 123 days | – |
| Metlakatla 6 S 105 ft | April 14 1 in 10 after May 1 | October 25 1 in 10 by October 8 | 194 days | 8a |
| Nenana Muni Airport 360 ft | May 15 1 in 10 after May 29 | September 11 1 in 10 by August 27 | 119 days | – |
| Nome Muni Airport 13 ft | June 5 1 in 10 after June 26 | September 3 1 in 10 by August 15 | 90 days | – |
| Northway Airport 1,713 ft | May 26 1 in 10 after June 8 | September 1 1 in 10 by August 18 | 98 days | – |
| Nuiqsut Airport 57 ft | A freeze is possible in any month | 2a | ||
| Palmer Muni Airport 230 ft | May 6 1 in 10 after May 18 | September 25 1 in 10 by September 11 | 142 days | 5a |
| Petersburg 1 107 ft | April 29 1 in 10 after May 14 | October 17 1 in 10 by September 30 | 171 days | 7b |
| Port Alsworth 1 SW 321 ft | June 2 1 in 10 after June 13 | September 12 1 in 10 by August 29 | 102 days | 4a |
| Portage Glacier V C 103 ft | May 27 1 in 10 after June 11 | September 12 1 in 10 by August 24 | 108 days | – |
| Ruby 44 ESE 259 ft | May 22 1 in 10 after June 3 | September 3 1 in 10 by August 21 | 104 days | – |
| Sand Point 1 ENE 240 ft | May 11 1 in 10 after May 25 | October 18 1 in 10 by October 4 | 160 days | – |
| Seldovia Airport 29 ft | May 10 1 in 10 after May 24 | October 1 1 in 10 by September 17 | 144 days | 6b |
| Seward Airport 22 ft | May 2 1 in 10 after May 17 | October 7 1 in 10 by September 28 | 158 days | 5b |
| Sitka 1 NE 78 ft | May 3 1 in 10 after May 19 | October 18 1 in 10 by October 1 | 168 days | – |
| Sitka Airport 14 ft | April 12 1 in 10 after April 30 | November 1 1 in 10 by October 13 | 203 days | – |
| Skagway Airport 20 ft | April 21 1 in 10 after May 2 | October 17 1 in 10 by October 1 | 179 days | 5a |
| Skwentna 150 ft | May 23 1 in 10 after June 4 | September 9 1 in 10 by August 26 | 109 days | – |
| St George Island Airport 125 ft | May 31 1 in 10 after June 23 | October 5 1 in 10 by September 17 | 127 days | 7a |
| St Paul Island Airport 35 ft | June 4 1 in 10 after June 25 | September 28 1 in 10 by September 11 | 116 days | 6b |
| St. Paul 4 NE 20 ft | June 5 1 in 10 after July 1 | September 28 1 in 10 by September 3 | 115 days | 6b |
| Talkeetna Airport 350 ft | May 16 1 in 10 after May 28 | September 16 1 in 10 by September 1 | 123 days | – |
| Tanana Calhoun Mem Airport 227 ft | May 29 1 in 10 after June 16 | August 28 1 in 10 by August 10 | 91 days | 1b |
| Tok 70 SE 2,000 ft | A freeze is possible in any month | – | ||
| Toolik Lake 5 ENE 2,461 ft | A freeze is possible in any month | – | ||
| Utqiagvik Formerly Barrow 4 EN 15 ft | A freeze is possible in any month | 2b | ||
| Valdez WSO 95 ft | April 30 1 in 10 after May 10 | October 2 1 in 10 by September 20 | 155 days | 5a |
| Wainwright Airport 30 ft | A freeze is possible in any month | 2b | ||
| Yakutat 3 SSE 26 ft | May 13 1 in 10 after May 29 | September 26 1 in 10 by September 13 | 136 days | 6b |
| Yakutat State Airport 33 ft | May 20 1 in 10 after May 31 | September 23 1 in 10 by September 5 | 126 days | 6b |
The average date is NOAA's 50% date: half of years have a later last frost, or an earlier first one. Plan by the 1-in-10 date if a freeze would cost you plants. Stations are NOAA's main weather stations, mostly airports. “Zone nearby” is the USDA 2023 zone of the nearest ZIP code within 10 miles. NOAA counts the frost season from August to July, so in the warmest places the “first fall” freeze lands after New Year.
How these dates work
Frost dates come from NOAA's 1991 to 2020 Climate Normals, which work out from each weather station's daily lows how likely the last spring freeze and the first fall freeze (32 °F) are by each date. We use the station nearest the middle of your ZIP code and show its height and distance, since a station on a hill or by a lake can differ from your yard.
The average date is the 50% date: half of years have a freeze after the spring date or before the fall one. The 1-in-10 dates are NOAA's 10% dates, the ones to plan by if a late freeze would cost you plants. Within one yard, cold air pools in low spots while walls and paving hold heat, so some corners freeze before others.
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Where the numbers come from
- USDA Plant Hardiness Zone Map, 2023. Agricultural Research Service, U.S. Department of Agriculture
- PRISM Climate Group, Oregon State University (zone data)
- NOAA NCEI, U.S. Climate Normals 1991–2020, annual/seasonal
- NOAA, Normals calculation methodology (frost-freeze probability dates)
- US Census Bureau, 2025 ZCTA gazetteer (ZIP code centers)