A whirlwind of rain and snow will blanket most of Canada this winter thanks in part to the La Nina weather pattern, according to the Farmers' Almanac's new extended weather forecast.

From east of the Rockies to Ontario, about two-thirds of Canada are projected to have below-normal temperatures as the La Nina system is forecast to develop throughout the season, according to the Farmers' Almanac, an online and print weather-forecasting publication based in Lewiston, Maine.

La Nina is a naturally occurring phenomenon that typically happens every three to five years, according to the National Oceanic and Atmospheric Administration. With La Nina, the interactions between the ocean surface and atmosphere make the tropical Pacific Ocean colder than normal. The changes affect tropical rainfall patterns and atmospheric winds over the ocean, which ultimately alter weather patterns around the world. While it usually forms during March to June, La Nina reaches "peak intensity" during winter and tends to last one to three years. 

Where and when will it be colder?

Marking the first day of winter, the winter solstice on Dec. 21 is the shortest day and longest night of the year in the Northern Hemisphere. The coldest temperatures are expected to hit areas from the The Prairies to the Great Lakes region.

The new year calls for Canadians to bundle up even more. The frigid air will cause temperatures to plummet the most during the final week of January into the start of February, from the Prairies into the Great Lakes region.

While British Columbia will be unseasonably chilly, Quebec and the Maritimes are projected to see temperatures that are higher than normal.

Wet and white winters

The eastern third of Canada is predicted to receive above-normal precipitation, especially around the Great Lakes.

If you're in the Newfoundland and Labrador regions, an umbrella or waterproof gear will come in handy for most of winter. The regions are expected to have a wet winter overall with some snow. Most of the precipitation will be "wet, mushy and slushy" amid projected higher-than-normal temperatures, according to the Farmers' Almanac.

A wet winter is also in the forecast for British Columbia.

Meanwhile in Quebec, snow will be more common during the season. A "decent sized storm" is forecast during the middle of February.

It's a mixed bag of snow and rain for Ontario. The Prairies are expected to have the best chance for a white winter.

Storm prediction

A storm is forecast to strike most eastern areas in the new year, bringing abundant snow, rain, sleet and ice as well as strong winds from Jan. 20 to 23 and 24 to 27.

How the Farmers' Almanac predicts weather

Founded in 1818, the Farmers' Almanac has been using a weather-forecasting formula that "has been time-tested, challenged, and approved for centuries," the publication wrote on its website.

Though it acknowledges that weather forecasting is an "inexact science," it said many of its followers believe its forecasts are 80 to 85 per cent accurate.

Founding editor David Young devised the formula, which considers sunspot activity, the moon's cyclical and predictable movements, past weather patterns, current conditions and the position of the planets.

Forecasts are made two years in advance and are never updated once published, Farmers' Almanac says.

Correction:

This story has been updated to correct the title of Farmers' Almanac and information about how it predicts weather. The story previously contained incorrect references to the Old Farmer's Almanac, which is a different publication from Farmers' Almanac.