More counterexamples. Coldest since at least 1924. Perhaps much longer.
Weather summary for New Brunswick issued by Environment Canada
The following station set a daily minimum temperature record on December 19, 2016:
Kouchibouguac Nat’l Park
New record of -24.5 C (-12.1 F)
Old record of -24.4 C (-11.9 F) set in 1942
Records in this area have been kept since 1924