The CBC Pollcast, hosted by CBC poll analyst Éric Grenier, explores the world of electoral politics, political polls and the trends they reveal.

With elections in three provinces, municipal votes pending in some of Canada's largest cities and a crucial midterm election in the United States, 2018 will be a big year in Canadian and international politics.

But it wouldn't be politics without a few surprises. What are some of the unlikely — but still plausible — events and decisions that could occur in the coming year?

Patrick Brown's Progressive Conservatives appear to be in a good position to remove Ontario Premier Kathleen Wynne, from office in June's election. But could Wynne pull off an upset and extend the life of her party's 15-year run, despite her rock-bottom approval ratings?

Might the New Democrats under Andrea Horwath instead manage a repeat of the 1990 surprise that brought their party under Bob Rae into power?

Will the federal leader of the NDP, Jagmeet Singh, finally decide to run for a seat in the House of Commons? Might the Democrats not just edge out the Republicans for control of the House of Representatives in the November midterms but instead storm both chambers to take complete control of Congress?

And could Justin Trudeau's Liberals make a few difficult political decisions that could impact their re-election chances in 2019?

To explain why the unlikely could still happen in 2018, Pollcast host Éric Grenier is joined by the CBC's Alison Crawford and Aaron Wherry.

Listen to the full discussion above — or subscribe to the CBC Pollcast and listen to past episodes.​

Follow Éric Grenier, Alison Crawford and Aaron Wherry on Twitter.