Mary's Harbour has a
subarctic climate (
Koppen: Dfc) with cold winters in spite of its marine position, courtesy of the cold waters of the
Labrador Current. Being located on the same latitude around from almost frost-free areas of
Ireland, the difference between the two Atlantic coastlines is rather extreme. As typical of eastern Canada, Mary's Harbour receives heavy snowfall each winter. Unusually for such a climate, it has a pronounced
seasonal lag, especially in the summer, with September averaging warmer than June and October warmer than May. A more typical subarctic climate, like
Oymyakon,
Russia has a temperature lag of only about 15 days. == Demographics ==