The dead of winter. Think hunched shoulders, chilblained toes and chronic cabin fever: in other words, the most intensely awful test of the season.

Now, Environment Canada's senior climatologist, Dave Phillips, has determined exactly when Canadians can expect that misery to arrive, no matter where they live.

For Ottawa and the rest of Central Canada, the dead of winter is dead ahead. In the capital, it hits Sunday, Jan. 19. Toronto gets its dose three days later.

Phillips achieved such precision by crunching temperature data spanning 30 years, from 1981 to 2010, and determining where the lowest lows tend to occur. Climate change may cause shifts here and there, but average highs and lows remain relative, according to Phillips.

The 'Dead of Winter' is an expression, but senior climatologist Dave Phillips has crunched the numbers over the past 30 years to determine its scientific date -- and it's different in every province. 7:22

Don't confuse the dead of winter with the winter solstice on Dec. 21, the shortest, darkest day of the year.

"There's a little piece of folklore which is quite apropos: 'As the days lengthen, the cold strengthens,'" Phillips said.

But don't despair. By the dead of winter, "you can say statistically there's more winter behind me than ahead of me," Phillips pointed out. "You've broken the back of winter."

Many of us have heard the phrase "the dead of winter" bandied about in the weeks after the holidays — but what does it really mean? The CBC's Hallie Cotnam set out to ask some Ottawa residents. 0:47

Photo challenge

CBC Ottawa is searching for the photos and memes that best capture the frozen misery that is the dead of winter.

We'll share the best — or is that worst? — examples here.

Send your entries to cbcnewsottawa@cbc.ca or via Twitter @cbcottawa.