The study by the School of Public Policy looked at shelter use by individuals described as "rough sleepers" - people who would normally choose to sleep on the street rather than move inside.
One of the authors, Ron Kneebone, says even though the number of people using the shelters peaks during the dead of winter, there is also a spike in late fall and into the spring.
He says bone-chilling cold is the main reason people move into a shelter but rain and sleet along with warmer temperatures also sends the homeless indoors.
Kneebone says the Alberta government works with shelter operators and provides extra money for the winter months but might want to look at extending the assistance into the spring.
He says unpredictable spring weather leads many of Calgary's 3,500 homeless to seek shelter during the worst storms.
"The shelters and the provincial government can learn that just because the cold weather is gone doesn't mean you won't get large, weather-driven spikes in shelter space," said Kneebone.
"Our study shows in Calgary, April is a particularly important month that results in large spikes in people from the street into homeless shelters."
Kneebone said the provincial government and Calgary's seven homeless shelters work closely to determine when the greatest demand will be for shelter use.
"The province provides extra money to shelter operators for the winter months. I'm hoping when they read this study they will extend that extra funding into April."
The study looks only at shelter use in Calgary. Kneebone said similar data should be gathered in other major cities. He said Vancouver, for example, would have a different demand because of the rainfall.
Winnipeg is much colder than Calgary but the weather tends to be drier, he noted.
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