BURLINGTON -- Temperatures in Vermont have risen by about 1.7 degrees over the last half century and they are projected to rise by between 2 and 3.6 degrees by mid-century, but the warming climate could have unexpected snow benefits in the short term, according to a study released Tuesday on the future of the state's climate.

Precipitation is increasing

Precipitation is increasing and heavy rainfall events are becoming more common, said the Vermont Climate Assessment released during a conference at the University of Vermont. The dates of the first freeze are getting later and the date of the last frost is getting earlier, the study found.

However, in what is being called a "sweet spot" of global warming, the state's ski areas can expect to see increased snowfall over the next 25 years. After that, most winter precipitation is expected to fall as rain, reducing the amount of snow available for skiing and other winter recreation, the report found.

"What we don't know, going back to this climate change sweet spot, is how people will actually behave," said Sam Carlson, a graduate student who helped write the assessment produced by UVM's Gund Institute for Ecological Economics. "People in the Boston and New York metro areas, if they don't have snow outside their own door, will they come up to go skiing, will they come up to go snowmobiling? We don't know that."

The Vermont Climate Assessment was the state version of the National Climate Assessment, released last month by the White House, which outlined what its authors saw as the perils of climate change. The national report emphasized that warming and the wild weather that comes with it has changed daily lives across the country.

The Vermont report was researched and written by UVM scientists with help from the National Weather Service, businesses and non-profit groups. The authors say the Vermont report is expected to be the first of many state-level efforts to understand the local effects of climate change.

A goal of the Vermont project is to help policy makers and scientists plan for a future of warmer temperatures and more extreme rainfalls, such as the series of 2011 rainstorms that culminated in Tropical Storm Irene. The warmer temperatures will also lengthen growing season and increase the suitable range for certain tree species, such as oak and hickory, while reducing it for others like spruce and fir.

The increased growing season could also present new challenges from different weeds, diseases and pests.

In Vermont, the authors used a wide variety of sources of information to show that temperatures are warming.

The report used information collected over the last 40 years by South Hero apple grower Ray Allen, which showed his trees are blooming about a week earlier than they used to. It also used information from the Joe's Pond ice-out contest -- a contest that has people pick the time when a cement block placed on the ice of the Danville pond falls through the ice and stops a clock attached to the block by a line -- that found the ice-out date is also happening an average of a week earlier.

"Joe's Pond is an example of very thorough, methodical science that was meant for prizes supporting the local Fourth of July celebration fund that has become a great record of changing climate," said UVM assistant professor Gillian Galford, the lead author of the report.