-17F here in northern NH.
It's not cold until the C and F thermometers read the same number.
In the 50s and 60s in northern Vermont that happened a lot.
One year in Worcester, VT it never got above -40F for a month.
I understand that northern NH & VT has colder temps than southern NH.
Just like ND has typical temperatures of -20 in the winter.
The coldest I have EVER seen prior to this morning in southern NH was -13.
In have always said real cold starts at a neg.30F