A chilly spring kept people from Minnesota state parks, but summer's attendance is looking sunnier.

The number of annual and daily vehicle permits sold — a key measure of attendance — was down 2.5 percent from January through August compared with the same period last year, according to data from the Minnesota Department of Natural Resources.

Summer months, though, were up: From Memorial Day weekend through Labor Day, permit sales surpassed last year's by 7.9 percent. Daily permit sales, which tend to rise and fall with the thermometer, rose 8.6 percent over that period, ending Sept. 2.

Total vehicle permit sales are up slightly this year from 2012. So far, the department has sold $3.5 million in passes.

"We are rebounding from a slow start with the late spring," said Amy Barrett, a spokeswoman for the Minnesota DNR. The department expects that "with a good fall," attendance ought to surpass last year's.

On Sunday, Mark Coffey of Minneapolis stopped by Gooseberry Falls State Park to show his 3-year-old son the cascading water during a family trip along the North Shore. At "every park we drove by" along the way, Coffey noticed a jumble of cars.

It was probably because of the "perfect" weather, he said. "A little cool in the morning, 75 degrees during the day."

Park attendance is "totally weather dependent," said Audrey Butts, park manager at Gooseberry. Late snow and spring showers hurt May and June numbers, she said. But the rain did bring with it "nicer waterfalls."

When it rains several weekends in a row, "people get out of the habit of thinking about coming out to parks," said Elaine Feikema, park manager at Nerstrand-Big Woods State Park, south of the Twin Cities. But in July and August, attendance rebounded. Camping over Labor Day weekend was full.

"You can't get any more than full," Feikema said.

The number of daily and annual permits sold at Fort Snelling State Park — 11,552 from January through August — was down 1 percent compared with the same period last year. Revenues were nearly even. But summer sales are up 11.7 percent.

Another spokeswoman for the DNR, Pat Arndt, said the shift matches anecdotes she has heard from park staffers about park usage. Data suggest visitors have returned to the parks in recent weeks, especially over July 4th weekend, Arndt said.

"There was kind of a pent-up demand," she said.

The Associated Press contributed to this report.

Jenna Ross • 612-673-7168