New research concludes climate change made last December's warm weather twice as likely.
December was warm across the country, but especially in the Prairies, where all three provinces were at least seven degrees warmer than usual.
Andrew Pershing of the U-S-based science group Climate Central used a widely accepted tool called the climate shift index to analyze the warm spell.
He found the weather couldn't be accounted for simply by El Nino, a naturally occurring pattern of warm weather that is particularly strong this year.
He says the cause was clearly climate change.
Nathan Gillett, a federal climate scientist not involved in the study, says Pershing's findings agree with what he would have expected.