Last frost dates in Maine
82 NOAA weather stations in Maine have thirty years of frost records. The median station sees its last 32 °F night around May 8; across the state that ranges from Apr 21 to Jun 2, so pick the station nearest you rather than a state-wide figure.
| WOODLAND | Apr 21 | May 2 | Apr 9 | Oct 26 | 185 |
| LEWISTON | Apr 25 | May 6 | Apr 11 | Oct 19 | 177 |
| PORTLAND INTL JETPORT | Apr 26 | May 7 | Apr 16 | Oct 15 | 170 |
| ACADIA NP | Apr 27 | May 8 | Apr 15 | Oct 22 | 177 |
| AUGUSTA STATE AP | Apr 27 | May 7 | Apr 15 | Oct 16 | 172 |
| NEWCASTLE | Apr 27 | May 10 | Apr 16 | Oct 18 | 172 |
| TENANTS HARBOR | Apr 27 | May 8 | Apr 17 | Oct 25 | 178 |
| W ROCKPORT 1 NNW | Apr 27 | May 9 | Apr 17 | Oct 19 | 175 |
| GRAY | Apr 28 | May 10 | Apr 15 | Oct 19 | 172 |
| WESTPORT ISLAND | Apr 28 | May 9 | Apr 16 | Oct 21 | 175 |
| EASTPORT | Apr 29 | May 11 | Apr 16 | Oct 25 | 178 |
| WINDHAM 2NW | Apr 30 | May 12 | Apr 18 | Oct 20 | 172 |
| CAPE NEDDICK | May 1 | May 14 | Apr 20 | Oct 14 | 165 |
| GARDINER | May 1 | May 14 | Apr 20 | Oct 11 | 163 |
| ORONO | May 1 | May 14 | Apr 22 | Oct 6 | 157 |
| TURNER | May 1 | May 13 | Apr 19 | Oct 10 | 162 |
| BRUNSWICK NAS | May 2 | May 14 | Apr 24 | Oct 10 | 160 |
| WATERVILLE TRTMT PLT | May 2 | May 14 | Apr 23 | Oct 10 | 159 |
| WESLEY | May 2 | May 12 | Apr 21 | Oct 15 | 164 |
| JONESBORO | May 3 | May 16 | Apr 22 | Oct 9 | 158 |
| POLAND | May 3 | May 16 | Apr 23 | Oct 7 | 157 |
| BANGOR INTL AP | May 4 | May 17 | Apr 24 | Oct 4 | 152 |
| GRAND LAKE STREAM | May 4 | May 18 | Apr 24 | Oct 10 | 157 |
| LINCOLN SANITARY DISTRICT/WTP | May 4 | May 16 | Apr 25 | Oct 6 | 153 |
| RUMFORD 1 SSE | May 4 | May 17 | Apr 23 | Oct 6 | 155 |
| BRIDGTON 3 NW | May 5 | May 17 | Apr 26 | Oct 5 | 151 |
| ROBBINSTON | May 5 | May 18 | Apr 24 | Oct 13 | 160 |
| BETHEL 6 SSE | May 6 | May 19 | Apr 27 | Oct 2 | 147 |
| E SANGERVILLE | May 6 | May 20 | Apr 25 | Oct 7 | 153 |
| FRENCHVILLE AROOSTOOK AP | May 6 | May 21 | Apr 25 | Oct 2 | 147 |
| HARTFORD | May 6 | May 21 | Apr 24 | Oct 3 | 148 |
| TOPSFIELD 2 | May 6 | May 18 | Apr 26 | Oct 8 | 155 |
| BELFAST | May 7 | May 21 | Apr 28 | Oct 5 | 151 |
| CARIBOU MUNI AP | May 7 | May 24 | Apr 27 | Oct 1 | 143 |
| GREENVILLE MAINE FORESTRY SVC | May 7 | May 20 | Apr 27 | Oct 9 | 153 |
| NEW SHARON | May 7 | May 22 | Apr 28 | Oct 2 | 146 |
| WEST BUXTON 2 NNW | May 7 | May 18 | Apr 28 | Oct 4 | 148 |
| CORINNA | May 8 | May 23 | Apr 27 | Oct 3 | 148 |
| E SURRY | May 8 | May 23 | Apr 27 | Oct 9 | 152 |
| MADISON | May 8 | May 20 | Apr 28 | Oct 5 | 149 |
| MILLINOCKET MUNI AP | May 8 | May 24 | Apr 27 | Oct 1 | 143 |
| WISCASSET AP | May 8 | May 20 | Apr 26 | Oct 7 | 151 |
| KENNEBUNKPORT | May 9 | May 22 | Apr 28 | Oct 3 | 146 |
| MILLINOCKET | May 9 | May 24 | Apr 28 | Oct 5 | 147 |
| BATH | May 10 | May 23 | Apr 28 | Oct 6 | 149 |
| HARMONY | May 11 | May 25 | Apr 30 | Oct 1 | 141 |
| LIVERMORE FALLS 1 E | May 11 | May 24 | Apr 29 | Sep 29 | 138 |
| BARNARD | May 12 | May 26 | Apr 30 | Oct 1 | 141 |
| EAST HIRAM | May 12 | May 25 | May 1 | Oct 1 | 140 |
| RUMFORD 6SW | May 12 | May 27 | Apr 30 | Sep 29 | 139 |
| LONG FALLS DAM | May 13 | May 27 | Apr 30 | Sep 30 | 138 |
| MOOSEHEAD | May 13 | May 29 | May 2 | Sep 30 | 137 |
| OLD TOWN 2 W | May 13 | May 28 | Apr 30 | Sep 28 | 137 |
| PATTEN 2 | May 13 | May 30 | May 1 | Sep 30 | 138 |
| VANCEBORO NO 2 | May 13 | May 28 | Apr 30 | Oct 1 | 139 |
| HOLLIS | May 14 | May 28 | May 3 | Sep 30 | 136 |
| PRESQUE ISLE | May 14 | Jun 1 | Apr 30 | Sep 26 | 131 |
| DOVER-FOXCROFT WWTP | May 15 | May 28 | Apr 30 | Sep 28 | 134 |
| DURHAM | May 15 | May 28 | May 1 | Oct 2 | 139 |
| FARMINGTON | May 16 | Jun 1 | May 3 | Sep 26 | 130 |
| LIMESTONE 4 NNW | May 16 | Jun 1 | May 1 | Sep 24 | 129 |
| SANFORD 2 NNW | May 16 | May 29 | May 2 | Sep 30 | 136 |
| SEBEC LAKE | May 16 | Jun 1 | May 3 | Oct 1 | 135 |
| FRYEBURG E SLOPES AP | May 17 | Jun 1 | May 2 | Sep 25 | 128 |
| MILLINOCKET WASTEWATER | May 17 | May 31 | May 1 | Sep 29 | 133 |
| ANDOVER 2 | May 19 | Jun 1 | May 5 | Sep 25 | 129 |
| HOULTON 5N | May 19 | Jun 2 | May 3 | Sep 23 | 125 |
| MIDDLE DAM | May 19 | May 31 | May 5 | Oct 1 | 133 |
| PITTSTON FARM | May 20 | Jun 3 | May 6 | Sep 23 | 123 |
| PITTSTON FARMS NEPP | May 21 | Jun 4 | May 8 | Sep 21 | 122 |
| BRASSUA DAM | May 23 | Jun 4 | May 7 | Sep 29 | 128 |
| FT KENT | May 23 | Jun 6 | May 8 | Sep 24 | 121 |
| RANGELEY | May 23 | Jun 3 | May 10 | Sep 27 | 127 |
| RANGELEY 2 NW | May 23 | Jun 5 | May 9 | Sep 24 | 123 |
| VAN BUREN 2 | May 23 | Jun 5 | May 8 | Sep 26 | 125 |
| EUSTIS | May 24 | Jun 6 | May 8 | Sep 21 | 118 |
| BRIDGEWATER | May 25 | Jun 7 | May 9 | Sep 18 | 115 |
| DANFORTH | May 25 | Jun 8 | May 10 | Sep 24 | 119 |
| JACKMAN | May 26 | Jun 7 | May 10 | Sep 23 | 119 |
| HOULTON INTL AP | May 27 | Jun 10 | May 9 | Sep 18 | 115 |
| CLAYTON LAKE | May 30 | Jun 12 | May 12 | Sep 13 | 106 |
| ALLAGASH | Jun 2 | Jun 21 | May 21 | Sep 15 | 102 |
How to read the three dates
Average is the date by which, in half of the years between 1991 and 2020, the last 32 °F night had already happened. Safe is later: only one year in ten saw a frost after it, which is the date to set out frost-tender plants such as dahlia tubers and zinnia seedlings. Early is the risky end, with a frost after it in nine years out of ten.
Every figure is for the weather station, not for your garden. A valley bottom, a north slope or a spot near a lake can run a week or two either way. Cities are warmer than the countryside around them.
Where the numbers come from
The dates are NOAA's U.S. Climate Normals for 1991 to 2020, computed by the National Centers for Environmental Information for every station with thirty years of daily minimum temperatures. ZIP codes are matched to the nearest such station within 150 km using U.S. Census Bureau ZIP Code Tabulation Area centroids. Stations that never see a frost, such as much of south Florida, report no date and are left out.