More counterexamples. Record lows in both New Brunswick and Nova Scotia. One record goes back to 1881, another back to 1883.
NEW BRUNSWICK
Weather summary by Environment Canada
The following stations set a daily minimum temperature record on December 16, 2016:
Grand Manan
New record of -20.9 C (-5.6 F)
Old record of -20.0 (-4.0 F) set in 1883
Records in this area have been kept since 1883Miscou Island
New record of -15.2 (4.6 F)
Old record of -14.1 (6.6 F) set in 2004
Records in this area have been kept since 1957
NOVA SCOTIA
The following stations set a daily minimum temperature record on December 16, 2016:
Brier Island
New record of -15.1 (4.8 F)
Old record of -12.8 (9.0 F) set in 1951
Records in this area have been kept since 1937Yarmouth
New record of -15.6 (3.9 F)
Old record of -15.0 (5.0 F) set in 1881
Records in this area have been kept since 1871
Via Ice Age Now