Yesterday, a hot, humid haze settled over Boston like a regional steam bath, and I couldn’t step outside the air-conditioned cocoon of my bedroom without erupting into beady sweat—forehead, chest, fingers, ankles—all puffing into plump, lethargic lumps. I holed up writing gibberish perfume reviews until the artificial chill turned stale, Dictionary.com’s cleft-palate charity ad bummed me out, and Mr. P returned from his Sunday morning triathlon to whisk me away to Crane Beach in Ipswich.

It wasn’t an archetypal beach day—an opaque scrim of gray clouds dulled the sky, and a fresh sea breeze across the 65-degree water made swimming feel like penance. But Mr. P liked how it reminded him of the beaches in Brittany, and I liked how I could bare my pale skin without worrying about sunscreen. We parked our beach chairs between a young family constructing a sandcastle at the command of a barky toddler and a silent blanket of teenage sunbathers who communicated solely through the crunch of Pringles.

While we ate our picnic lunch, Mr. P dropped his sandwich in the sand, giving me a perfect excuse to trot out that old chestnut—“that’s why they’re called sandwiches”—which made him laugh, thinking I’d made it up. Afterward, while he dove into the New York Times and took discreet sips from his beer, I wandered off for a walk.

Crane Beach is one of my favorite spots in New England—a long white ribbon of silky sand unfurling around billowy dunes. Further down, past the crowds and lifeguards, the ocean flattens at low tide into wide, shallow pools. You can wade out nearly a third of a mile and still be dry above the knees. Shoals of sand rise like islands from the water, empty but for the clams exhaling air holes at your feet.

I reached this stretch just as the tide began to pull back in. The shoals were shrinking, tidal pools draining into the murkier sea. Out on one of the sandbars, a man photographed a woman as she charged repeatedly at a group of piping plovers, scattering them like confetti, then retreating so they’d return. I walked the rippled flats alone, letting the grooves of the sand exfoliate the skin of my soles. The water no longer felt glacial. It felt perfect.

I turned and began walking back toward the main beach—toward the crowds, the lifeguards, Mr. P. As the water reached my knees, I stepped onto a vanishing shoal to slip off the army-green J.Crew shorts I’d modestly worn over my swimsuit. Soon the tide kissed my waist. The ocean gathered strength. I lengthened my stride, enjoying the renewed resistance against my legs. I’d left the shoals and flats behind and entered the ocean proper.

And then the bottom dropped out.

I dropped the shorts and started swimming backstroke, hard. Within seconds, my feet found the bottom again—thigh-high water, safety. Two fishermen on the shore watched me wade back toward the beach, toward the lifeguards, toward Mr. P. From the way they looked at me, I knew they’d seen me flailing. They’d been debating whether they needed to dive in.

But I didn’t need rescuing.

I just needed the nerve to let my shorts get wet.

[Below is a picture at Crane Beach from October 2007, taken by Mr. P at low tide. The rippled sand flats are visible beneath the horse.]