Last frost dates in Maryland
43 NOAA weather stations in Maryland have thirty years of frost records. The median station sees its last 32 °F night around Apr 8; across the state that ranges from Mar 22 to May 9, so pick the station nearest you rather than a state-wide figure.
| SOLOMONS | Mar 22 | Apr 5 | Mar 6 | Nov 26 | 248 |
| ANNAPOLIS NAF | Mar 23 | Apr 6 | Mar 8 | Nov 20 | 241 |
| MD SCI CTR BALTIMORE | Mar 24 | Apr 4 | Mar 8 | Nov 21 | 244 |
| ANNAPOLIS POLICE BRKS | Mar 27 | Apr 9 | Mar 9 | Nov 13 | 234 |
| NATL ARBORETUM DC | Mar 29 | Apr 11 | Mar 15 | Nov 8 | 224 |
| PATUXENT RIVER NAS | Mar 29 | Apr 10 | Mar 15 | Nov 15 | 230 |
| STEVENSVILLE 2SW | Mar 29 | Apr 8 | Mar 15 | Nov 12 | 228 |
| ST INIGOES WEBSTER NOLF | Mar 30 | Apr 11 | Mar 14 | Nov 14 | 229 |
| ASSATEAGUE | Mar 31 | Apr 13 | Mar 15 | Nov 15 | 228 |
| ROCKVILLE 1 NE | Apr 1 | Apr 15 | Mar 19 | Nov 6 | 219 |
| ROYAL OAK 2 SSW | Apr 1 | Apr 15 | Mar 18 | Nov 7 | 220 |
| CYLBURN | Apr 2 | Apr 13 | Mar 20 | Nov 7 | 220 |
| FREDERICK POLICE BRKS | Apr 2 | Apr 15 | Mar 17 | Nov 6 | 218 |
| SALISBURY 2N | Apr 2 | Apr 16 | Mar 16 | Nov 10 | 222 |
| CHESTERTOWN | Apr 3 | Apr 16 | Mar 20 | Nov 5 | 217 |
| CONOWINGO DAM | Apr 3 | Apr 18 | Mar 22 | Nov 6 | 217 |
| OXON HILL | Apr 3 | Apr 15 | Mar 19 | Nov 8 | 217 |
| SALISBURY | Apr 3 | Apr 25 | Mar 18 | Nov 7 | 217 |
| LAUREL 3 W | Apr 5 | Apr 19 | Mar 21 | Nov 9 | 218 |
| HAGERSTOWN WASHINGTON CO AP | Apr 7 | Apr 21 | Mar 25 | Nov 4 | 209 |
| OCEAN CITY MUNI AP | Apr 7 | Apr 23 | Mar 24 | Nov 2 | 209 |
| VIENNA | Apr 8 | Apr 23 | Mar 24 | Nov 4 | 209 |
| DALECARLIA RSVR | Apr 9 | Apr 26 | Mar 27 | Oct 31 | 202 |
| UPPER MARLBORO 3 NNW | Apr 9 | Apr 24 | Mar 27 | Oct 29 | 203 |
| ABERDEEN PHILLIPS FLD | Apr 10 | Apr 30 | Mar 27 | Oct 30 | 201 |
| BALTIMORE WASH INTL AP | Apr 10 | Apr 25 | Mar 27 | Oct 31 | 204 |
| BELTSVILLE | Apr 10 | May 1 | Mar 27 | Nov 1 | 202 |
| SALISBURY WICOMICO RGNL AP | Apr 10 | Apr 30 | Mar 28 | Oct 30 | 201 |
| SNOW HILL 4 N | Apr 10 | Apr 28 | Mar 27 | Oct 31 | 202 |
| HAGERSTOWN 1 E | Apr 11 | Apr 27 | Mar 29 | Oct 28 | 199 |
| CATOCTIN MTN PARK | Apr 14 | Apr 30 | Apr 2 | Oct 30 | 197 |
| DAMASCUS 3 SSW | Apr 14 | May 2 | Mar 31 | Oct 29 | 196 |
| CUMBERLAND 2 | Apr 15 | May 5 | Apr 2 | Oct 24 | 190 |
| MECHANICSVILLE 5 NE | Apr 17 | May 2 | Mar 31 | Oct 27 | 195 |
| MILLERS 4 NE | Apr 19 | May 8 | Apr 4 | Oct 25 | 188 |
| EMMITSBURG 2 SE | Apr 22 | May 9 | Apr 7 | Oct 20 | 179 |
| GLENN DALE BELL STN | Apr 22 | May 9 | Apr 3 | Oct 22 | 183 |
| SMITHSBURG 2NW | Apr 25 | May 11 | Apr 12 | Oct 19 | 176 |
| SHARPSBURG 5 S | Apr 26 | May 15 | Apr 11 | Oct 18 | 175 |
| FROSTBURG 2 | Apr 29 | May 15 | Apr 14 | Oct 18 | 171 |
| SAVAGE RVR DAM | Apr 29 | May 15 | Apr 11 | Oct 20 | 174 |
| OAKLAND 1 SE | May 6 | May 23 | Apr 21 | Oct 9 | 156 |
| SINES DEEP CREEK | May 9 | May 30 | Apr 21 | Oct 11 | 155 |
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.