Been talking to the neighbours of late, and what they've said about the local climate and weather rather fits in with my own, albeit anecdotal, observations. Cold snaps like the one we're currently experiencing seem to happen in approximate 10 and 20 year cycles. Mostly they're not as intense, but it still forms a pattern. Working backwards from 2007 / 2008 the colder weather was noted in 1996 & 1998, before that 1987 / 88, 1978 was supposedly cold and wintry, 1971 was one of those 'All Canada' events, rather like the early 1960's and 1950's. Before that we have no local information, and the Airport Weather records only go back to 1979.
This got me thinking. In the UK we had an exceptionally cold winter in 1947, I've no information on the 1950's to hand, so I can't include that, but I recall trudging to school through heavy snow in 1967. 1977 was particularly cold and snowy. 1981 / 82 was pretty rough where I lived. 1987 had a cold snap that saw our household cut off from power, water, everything for three complete days. 1997 had a few snowfalls if I recall correctly, but nothing too exceptional, yet 2007 / 2008 have been distinctly chilly.
Again; this is all anecdotal based on memory so the years may be out, but the approximate 10 and 20 year cycles are definitely there. I'd have to check some impartial temperature records to be sure, along with precipitation measures etc. These cold weather events appear more driven by solar activity and major volcanic events than anthropomorphic causes.
Funny what a bit of a gossip with people whose memories go back further than the official temperature records will turn up.