Golfers, restaurant patio owners and sun worshippers rejoice - weather forecasters are calling for a hotter-than-normal summer for most of Alberta.

AccuWeather.com senior meteorologist Brett Anderson said the El Nino weather phenomenon is on its way and is expected to bring warmer-than-average temperatures to most of Canada, particularly the Prairies.

"The whole key to this summer is going to be longer, more prolonged heat," Anderson said.

"You're also going to see less in terms of rainfall," said Anderson.

In July and August, Calgary typically averages a daily high of 22 C. Anderson said this year, average temperatures could be two degrees higher than that.

But while that may sound good to outdoor enthusiasts, Anderson said it's part of a worrisome long-term warming trend.

"Over the past 10 years, the majority of them have been warmer than normal, and it looks like this summer will be no real exception," he said. "It's very concerning. As it gets hotter across the Prairies, it gets drier, and that's not a good thing."

Harry Brook, crop specialist with Alberta Agriculture, said farmers have got a great start to seeding this year, thanks to an early spring and timely rainfall. However, he said a drier than normal summer could be a problem, especially since so little snow fell over the winter.

"In most places in the province, the tap turned off after July last year. And we really didn't get any significant moisture events again until this spring, with the rain," Brook said. "So we do feel cautious, but it's early days. . . . And there's never been a year yet where people (farmers) haven't worried about a possible drought."

Environment Canada will not release a formal summer forecast until June 1, but its preliminary projections echo AccuWeather's - calling for warm, dry weather for southern and central Alberta and above average temperatures for most of the country. However, senior Environment Canada climatologist David Phillips said he doesn't have a lot of confidence in the forecast this early in the season.

"It's almost a crapshoot, in a way," Phillips said. "I certainly wouldn't plan an outdoor wedding based on the seasonal forecast. This is not a done deal."

Phillips said it is more difficult to make summer forecasts than winter forecasts, because the weather patterns that influence the season are not as large.

However, even in the winter, long-term forecasts can go spectacularly wrong - as evidenced this year, when both Environment Canada and AccuWeather.com predicted a colder-than-average winter.

The La Nina climate pattern was expected to hold the Prairies in a deep freeze, but instead, a phenomenon called "Arctic oscillation" trapped the cold air in the Far North and drew warm Pacific air east.

"We all screwed that one up," Anderson acknowledged. "You can't predict Arctic oscillation in a long-range forecast. You just can't know what it's going to do. And since it was so strong, it was unusual - it overwhelmed any impact La Nina might have had."

In addition to hot, dry weather across the Prairies, the AccuWeather summer forecast is calling for active, stormy weather across eastern Ontario and southern Quebec.

Atlantic Canada is expected to be warmer and more humid than normal, with a higher than-average risk of tropical storm activity.

The only areas of the country that are expected to be cooler than normal are parts of the West Coast.

astephenson@ calgaryherald.com