Anyone walking through Copley Square Wednesday at noon will get a little help beating the heat.

Members of the Headwear Association will give out free wide-brimmed hats on the first day of summer as part of the fourth annual “Hat Day in the Sun” event to aid people in the fight against skin cancer. Temperatures are expected in the 90s on Wednesday.

“This is our first time in ­Boston,” said Jill Hammer, publicist for the Headwear Association. “Everybody is out and about out there, so it should be pretty successful.”

Hammer said group members will be giving out 200 hats, but encouraged people to get there ahead of time. “I would say people should come early for sure. The hats go pretty quickly.”

Broner Hat and Glove, a family-owned company out of Detroit, will provide the hats. Hammer said anyone who wants a free hat just needs to fill out an informational survey.

Hammer stressed the importance of wearing hats that protect from the sun’s harmful rays.

“The most important thing is at least a 2½-inch brim,” she said. “It works out because some of the hottest styles right now are big-brimmed hats.”

She said many hats are given an ultraviolet protection factor, or UPF number, depending on how much of the sun’s ultra­violet rays the hat absorbs. Hammer said the hats that will be given out are all rated with a UPF of 50, meaning they allow 1/50 of the ultraviolet rays to reach the skin.

With nearly record-breaking heat predicted, Hammer said there is no better time for a good hat.

Salmagundi, a hat and accessory shop in Jamaica Plain owned by Jessen Fitzpatrick and his wife, Andria Rapagnola, will help distribute the hats. ­Salmagundi was named the ­National Hat Retailer of the year by the Headwear Association in 2011.

Fitzpatrick said he enjoys doing anything he can to promote hat awareness and is excited about the event.

“Last night I was looking at the high temperatures,” he said. “It’s perfect because it’s going to be so hot.”