This is likely due to a low level temperature inversion. You can see this on the mesonet website. There is a significant difference between Westminster and Clarksville.
To be absolutely clear, I love all of our NOAA/NWS partners. It's just sad that the public and Congress don't give our NWP folks the money they need to be #1.
RTMA 2m temp analysis shows we're not too far off from getting to freezing: https://www.pivotalweather.com/maps.php?data_type=obs&r=us_ma&p=sfct-imp&ds=rtma_ru
4 inch soil temperatures across Maryland haven't budged, which is good: