Some years it rains. Some years it snows. This year, St. Patrick brought summer.

The annual wearing of the green meant shorts and flip-flops with clover T-shirts and lime-colored wigs for people who lined the sunny streets of Gaithersburg on Saturday for the 12th annual St. Patrick’s Day parade.

Even though it’s still days away from the first day of spring, the parade had a beachy, bring-your-towel vibe.

Rachel and Kyle Langham slathered sunscreen on their 1-year-old daughter Abigail as a ladder truck from a volunteer fire department rolled by.

“She was complaining her skin was hot and blowing on my skin,” said Rachel Langham, 29, who lives in Damascus. “But I’m not complaining.”

Even though the mercury hovered in the low 70s, many parade watchers said it felt much warmer, probably because they were lined up four and five people deep to see the dancers, clowns and Girl Scout troops march by.

Charlene Dillingham, 50, came with her husband and two sons, just as they have every year for the past decade, almost since her boys were babies. They come as part tradition, part reconnaissance mission. Dillingham helps put on the spring parade in nearby historic Laytonsville, population 300. She comes to get tips on what works and what doesn’t.

“It’s going well,” Dillingham said with approval. “The spacing is nice, there’s no bunching up.”

Then a man dressed in a head-to-toe green nylon body covering a la Blue Man Group came bounding by.

“That’s kind of freaky,” she murmured.

She said she tries to put on the best parade possible but is careful with her expectations.

“My motto is, as long as nobody gets run over, it’s a good day,” she said.

Linda Morgan, treasurer of the Harp and Shamrock Society of Gaithersburg, which organizes the St. Patrick’s Day parade, said this year is their biggest showing yet, with 72 groups participating.

“Anyone can be in the parade,” Morgan said. “As long as they mind their manners.”

They had a problem a few years back with a political group that was handing out potentially offensive fliers, but police corralled them and stopped them, she said.

There were no such problems this year, as thousands of people, mostly families, came to celebrate their heritage, or just pretend to be Irish for the day.

Jennifer Sengbusch, 37, brought her husband and three children from Germantown for the parade. Their daughter Claire, 6, was one of the performers, dancing with the Culkin School of Irish Dance.

Dozens of small children wearing black lined up and danced in synchronized Irish steps, most with happy smiles.

“It’s a confidence boost for her to perform in front of other people,” Sengbusch said. “It’s been great for her.”

Even if Claire wasn’t performing, Sengbusch said they probably would have to come to the parade anyway.

“It’s a nice way to get out and have family time and be outside instead of home on the computer,” she said.

So went the balmy day celebrating the patron saint of Ireland. Everyone minded his and her manners, most notably Mother Nature.