Last frost dates in Wyoming
129 NOAA weather stations in Wyoming have thirty years of frost records. The median station sees its last 32 °F night around May 20; across the state that ranges from Apr 28 to Jun 24, so pick the station nearest you rather than a state-wide figure.
| Plan sowing from this date | ||||||
|---|---|---|---|---|---|---|
| BASIN | Apr 28 | May 11 | Apr 15 | Oct 10 | 164 | Plan sowing from this date → |
| GREYBULL S BIG HORN AP | May 4 | May 18 | Apr 22 | Oct 1 | 149 | Plan sowing from this date → |
| WORLAND | May 4 | May 18 | Apr 23 | Oct 1 | 149 | Plan sowing from this date → |
| BOYSEN DAM | May 5 | May 20 | Apr 23 | Oct 7 | 153 | Plan sowing from this date → |
| THERMOPOLIS | May 5 | May 19 | Apr 23 | Oct 5 | 152 | Plan sowing from this date → |
| DEAVER | May 6 | May 20 | Apr 26 | Oct 1 | 148 | Plan sowing from this date → |
| COLONY | May 7 | May 21 | Apr 26 | Oct 3 | 149 | Plan sowing from this date → |
| GUERNSEY 2NW | May 7 | May 21 | Apr 24 | Oct 6 | 152 | Plan sowing from this date → |
| SHOSHONI | May 7 | May 18 | Apr 27 | Oct 3 | 145 | Plan sowing from this date → |
| WHALEN DAM USBR | May 7 | May 24 | Apr 25 | Oct 3 | 146 | Plan sowing from this date → |
| GLENDO RSVR USBR | May 9 | May 24 | Apr 27 | Oct 5 | 148 | Plan sowing from this date → |
| LOVELL | May 9 | May 25 | Apr 27 | Sep 29 | 142 | Plan sowing from this date → |
| PATHFINDER DAM | May 9 | May 23 | Apr 28 | Oct 7 | 148 | Plan sowing from this date → |
| CASPER WWTP | May 10 | May 24 | Apr 30 | Sep 29 | 138 | Plan sowing from this date → |
| PINE BLUFFS 1ESE | May 10 | May 24 | Apr 30 | Oct 1 | 142 | Plan sowing from this date → |
| TENSLEEP 4NE | May 10 | May 26 | Apr 27 | Oct 1 | 141 | Plan sowing from this date → |
| GREYBULL | May 11 | May 24 | Apr 30 | Sep 23 | 133 | Plan sowing from this date → |
| GUERNSEY DAM #2 | May 11 | May 25 | Apr 29 | Oct 3 | 144 | Plan sowing from this date → |
| TORRINGTON MUNI AP | May 11 | May 26 | Apr 30 | Sep 29 | 139 | Plan sowing from this date → |
| CASPER 1SW | May 12 | May 26 | Apr 28 | Oct 1 | 143 | Plan sowing from this date → |
| CHEYENNE | May 12 | May 26 | May 1 | Oct 1 | 141 | Plan sowing from this date → |
| CODY | May 12 | May 27 | Apr 27 | Oct 1 | 140 | Plan sowing from this date → |
| EMBLEM | May 12 | May 27 | Apr 30 | Sep 28 | 136 | Plan sowing from this date → |
| RIVERTON | May 12 | May 26 | May 1 | Sep 24 | 132 | Plan sowing from this date → |
| SEMINOE RSVR USBR | May 12 | May 25 | May 1 | Oct 4 | 143 | Plan sowing from this date → |
| BUFFALO JOHNSON CO AP | May 13 | May 28 | Apr 28 | Oct 1 | 141 | Plan sowing from this date → |
| LANDER 11 SSE | May 13 | Jun 1 | May 1 | Oct 2 | 140 | Plan sowing from this date → |
| NEWCASTLE | May 13 | May 26 | Apr 30 | Oct 3 | 143 | Plan sowing from this date → |
| WORLAND | May 13 | May 27 | May 2 | Sep 26 | 133 | Plan sowing from this date → |
| ALBIN | May 14 | May 25 | May 2 | Oct 2 | 142 | Plan sowing from this date → |
| BLACK MTN | May 14 | Jun 1 | Apr 29 | Oct 3 | 140 | Plan sowing from this date → |
| CARPENTER 3N | May 14 | May 27 | May 4 | Sep 26 | 133 | Plan sowing from this date → |
| CHEYENNE WFO | May 14 | May 28 | May 3 | Oct 1 | 139 | Plan sowing from this date → |
| LA GRANGE | May 14 | May 29 | May 1 | Oct 1 | 137 | Plan sowing from this date → |
| LEITER 9N | May 14 | May 29 | Apr 30 | Sep 30 | 137 | Plan sowing from this date → |
| LUSK 25NE | May 14 | May 27 | May 2 | Oct 1 | 139 | Plan sowing from this date → |
| OLD FT LARAMIE | May 14 | May 27 | May 3 | Sep 26 | 134 | Plan sowing from this date → |
| PAVILLION | May 14 | May 29 | Apr 30 | Sep 30 | 139 | Plan sowing from this date → |
| TORRINGTON EXP FARM | May 14 | May 28 | May 2 | Sep 24 | 130 | Plan sowing from this date → |
| DULL CTR 1SE | May 15 | May 28 | May 3 | Sep 27 | 133 | Plan sowing from this date → |
| GILLETTE 4SE | May 15 | May 27 | May 1 | Oct 1 | 136 | Plan sowing from this date → |
| HEART MTN | May 15 | Jun 1 | May 1 | Sep 25 | 132 | Plan sowing from this date → |
| YODER 5 W | May 15 | Jun 2 | May 3 | Sep 27 | 132 | Plan sowing from this date → |
| PINE BLUFFS 5W | May 16 | Jun 1 | May 5 | Sep 27 | 132 | Plan sowing from this date → |
| REDBIRD | May 16 | May 31 | May 4 | Sep 24 | 130 | Plan sowing from this date → |
| RIVERTON | May 16 | May 31 | May 1 | Sep 28 | 133 | Plan sowing from this date → |
| SHELL | May 16 | Jun 3 | May 4 | Sep 24 | 130 | Plan sowing from this date → |
| BIG HORN | May 17 | May 31 | May 2 | Sep 28 | 132 | Plan sowing from this date → |
| BUFFALO BILL DAM | May 17 | Jun 3 | May 1 | Oct 3 | 136 | Plan sowing from this date → |
| HULETT | May 17 | May 30 | May 6 | Sep 23 | 128 | Plan sowing from this date → |
| LANCE CREEK 11NNE | May 17 | Jun 3 | May 5 | Sep 25 | 129 | Plan sowing from this date → |
| RAWLINS 1N | May 17 | May 31 | May 5 | Oct 2 | 138 | Plan sowing from this date → |
| TORRINGTON 29N | May 17 | May 31 | May 6 | Sep 28 | 133 | Plan sowing from this date → |
| CHUGWATER | May 18 | Jun 2 | May 5 | Sep 24 | 129 | Plan sowing from this date → |
| CLARK 3NE | May 18 | Jun 4 | May 6 | Sep 22 | 125 | Plan sowing from this date → |
| KAYCEE | May 18 | May 31 | May 5 | Sep 25 | 129 | Plan sowing from this date → |
| LANDER HUNT FLD AP | May 18 | Jun 3 | May 4 | Sep 27 | 131 | Plan sowing from this date → |
| SHERIDAN FLD STN | May 18 | Jun 2 | May 4 | Sep 24 | 127 | Plan sowing from this date → |
| BILLY CREEK | May 19 | May 31 | May 7 | Sep 21 | 123 | Plan sowing from this date → |
| DOUGLAS 1 SE | May 19 | Jun 2 | May 7 | Sep 23 | 126 | Plan sowing from this date → |
| POWELL FLD STN | May 19 | Jun 4 | May 5 | Sep 20 | 123 | Plan sowing from this date → |
| WHEATLAND 4 N | May 19 | Jun 2 | May 7 | Sep 22 | 125 | Plan sowing from this date → |
| LEO 6 SW | May 20 | Jun 13 | May 3 | Sep 28 | 128 | Plan sowing from this date → |
| LINGLE 2WSW | May 20 | Jun 7 | May 8 | Sep 22 | 122 | Plan sowing from this date → |
| UPTON | May 20 | Jun 4 | May 8 | Sep 23 | 123 | Plan sowing from this date → |
| ARCHER | May 21 | Jun 6 | May 8 | Sep 24 | 124 | Plan sowing from this date → |
| DIVERSION DAM | May 21 | Jun 6 | May 7 | Sep 20 | 119 | Plan sowing from this date → |
| ECHETA 2 NW | May 21 | Jun 3 | May 9 | Sep 23 | 123 | Plan sowing from this date → |
| MUDDY GAP | May 21 | Jun 10 | May 6 | Sep 27 | 126 | Plan sowing from this date → |
| PHILLIPS | May 21 | Jun 7 | May 8 | Sep 21 | 121 | Plan sowing from this date → |
| SHERIDAN CO AP | May 21 | Jun 6 | May 7 | Sep 23 | 123 | Plan sowing from this date → |
| SUNDANCE | May 21 | Jun 5 | May 9 | Sep 25 | 124 | Plan sowing from this date → |
| BATES CREEK #2 | May 22 | Jun 6 | May 8 | Sep 26 | 125 | Plan sowing from this date → |
| GILLETTE CAMPBELL AP | May 22 | Jun 4 | May 8 | Sep 25 | 125 | Plan sowing from this date → |
| LARAMIE 4SE | May 22 | Jun 4 | May 10 | Sep 28 | 126 | Plan sowing from this date → |
| MIDWEST | May 22 | Jun 6 | May 8 | Sep 22 | 121 | Plan sowing from this date → |
| MOORCROFT 3S | May 22 | Jun 9 | May 8 | Sep 28 | 127 | Plan sowing from this date → |
| ROCK SPRINGS AP | May 22 | Jun 9 | May 5 | Sep 28 | 126 | Plan sowing from this date → |
| SYBILLE RSCH UNIT | May 22 | Jun 5 | May 8 | Sep 24 | 125 | Plan sowing from this date → |
| TENSLEEP 16SSE | May 22 | Jun 7 | May 10 | Sep 18 | 117 | Plan sowing from this date → |
| DEVILS TWR #2 | May 23 | Jun 6 | May 12 | Sep 20 | 118 | Plan sowing from this date → |
| DOUGLAS CONVERSE CO AP | May 23 | Jun 7 | May 10 | Sep 22 | 122 | Plan sowing from this date → |
| LUSK 2 SW | May 23 | Jun 8 | May 9 | Sep 20 | 119 | Plan sowing from this date → |
| POWDER RIVER #2 | May 23 | Jun 5 | May 9 | Sep 20 | 121 | Plan sowing from this date → |
| SUNDANCE 8 NNW | May 23 | Jun 3 | May 10 | Sep 24 | 121 | Plan sowing from this date → |
| WESTON 1 E | May 23 | Jun 5 | May 11 | Sep 18 | 118 | Plan sowing from this date → |
| BUCKBOARD MARINA | May 24 | Jun 8 | May 11 | Sep 23 | 118 | Plan sowing from this date → |
| BUFFALO | May 24 | Jun 9 | May 12 | Sep 21 | 118 | Plan sowing from this date → |
| CLEARMONT 5 SW | May 24 | Jun 8 | May 12 | Sep 16 | 114 | Plan sowing from this date → |
| CODY 12SE | May 24 | Jun 11 | May 10 | Sep 15 | 114 | Plan sowing from this date → |
| DAYTON | May 24 | Jun 7 | May 11 | Sep 18 | 114 | Plan sowing from this date → |
| GREEN RVR | May 24 | Jun 10 | May 7 | Sep 22 | 120 | Plan sowing from this date → |
| ROCK SPRINGS FIRE DEPT | May 24 | Jun 9 | May 8 | Sep 24 | 121 | Plan sowing from this date → |
| STORY | May 24 | Jun 9 | May 10 | Sep 23 | 120 | Plan sowing from this date → |
| THERMOPOLIS 9NE | May 24 | Jun 9 | May 12 | Sep 16 | 112 | Plan sowing from this date → |
| CHURCH BUTTES GAS PLT | May 25 | Jun 11 | May 8 | Sep 27 | 124 | Plan sowing from this date → |
| DILLINGER | May 25 | Jun 8 | May 13 | Sep 17 | 113 | Plan sowing from this date → |
| GLENDO 6NE | May 25 | Jun 11 | May 13 | Sep 15 | 112 | Plan sowing from this date → |
| ROCHELLE 7ENE | May 25 | Jun 11 | May 11 | Sep 14 | 110 | Plan sowing from this date → |
| WRIGHT 12W | May 25 | Jun 8 | May 14 | Sep 23 | 120 | Plan sowing from this date → |
| CASPER NATRONA CO AP | May 26 | Jun 10 | May 12 | Sep 22 | 117 | Plan sowing from this date → |
| HECLA 1E | May 27 | Jun 13 | May 12 | Sep 19 | 115 | Plan sowing from this date → |
| WAPITI 1WSW | May 27 | Jun 12 | May 11 | Sep 25 | 121 | Plan sowing from this date → |
| ELK MTN | May 28 | Jun 13 | May 14 | Sep 13 | 108 | Plan sowing from this date → |
| CODY 21 SW | May 29 | Jun 17 | May 11 | Sep 18 | 110 | Plan sowing from this date → |
| THERMOPOLIS 21WNW | May 29 | Jun 19 | May 14 | Sep 17 | 110 | Plan sowing from this date → |
| POWDER RVR (SCHOOL) | May 30 | Jun 13 | May 12 | Sep 22 | 115 | Plan sowing from this date → |
| BAGGS | Jun 1 | Jun 18 | May 15 | Sep 18 | 108 | Plan sowing from this date → |
| BITTER CREEK 4 NE | Jun 1 | Jun 21 | May 15 | Sep 16 | 106 | Plan sowing from this date → |
| BURRIS | Jun 1 | Jun 19 | May 17 | Sep 14 | 104 | Plan sowing from this date → |
| JEFFREY CITY | Jun 1 | Jun 16 | May 17 | Sep 13 | 104 | Plan sowing from this date → |
| MEDICINE BOW | Jun 1 | Jun 19 | May 20 | Sep 8 | 97 | Plan sowing from this date → |
| RAWLINS MUNI AP | Jun 1 | Jun 17 | May 17 | Sep 15 | 105 | Plan sowing from this date → |
| CENTENNIAL 1NE | Jun 2 | Jun 20 | May 22 | Sep 19 | 106 | Plan sowing from this date → |
| DOUBLE FOUR RCH | Jun 2 | Jun 25 | May 18 | Sep 9 | 99 | Plan sowing from this date → |
| LARAMIE RGNL AP | Jun 2 | Jun 18 | May 21 | Sep 15 | 102 | Plan sowing from this date → |
| SARATOGA | Jun 2 | Jun 21 | May 15 | Sep 12 | 101 | Plan sowing from this date → |
| EVANSTON BURNS FLD | Jun 3 | Jun 17 | May 16 | Sep 25 | 113 | Plan sowing from this date → |
| YELLOWSTONE PARK MAMMOTH | Jun 3 | Jun 19 | May 18 | Sep 14 | 102 | Plan sowing from this date → |
| WAMSUTTER | Jun 5 | Jun 23 | May 20 | Sep 14 | 101 | Plan sowing from this date → |
| LARAMIE 2 NW | Jun 7 | Jun 29 | May 23 | Sep 4 | 88 | Plan sowing from this date → |
| LA BARGE | Jun 9 | Jun 27 | May 24 | Sep 4 | 84 | Plan sowing from this date → |
| EVANSTON 1 E | Jun 12 | Jul 2 | May 26 | Sep 12 | 90 | Plan sowing from this date → |
| SARATOGA 4N | Jun 12 | Jun 30 | May 25 | Sep 7 | 83 | Plan sowing from this date → |
| ALTA 1 NNW | Jun 14 | Jul 4 | May 23 | Sep 11 | 85 | Plan sowing from this date → |
| MTN VIEW | Jun 14 | Jul 1 | May 31 | Sep 9 | 84 | Plan sowing from this date → |
| AFTON | Jun 20 | Jul 7 | Jun 2 | Sep 1 | 71 | Plan sowing from this date → |
| MOOSE | Jun 20 | Jul 9 | Jun 5 | Aug 31 | 70 | Plan sowing from this date → |
| MOOSE 1 NNE | Jun 24 | Jul 11 | Jun 8 | Aug 28 | 63 | Plan sowing from this date → |
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 transplant tomatoes and peppers, both killed by a single frost. 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.