Penn's Cave is a natural cavern located in central Pennsylvania about 14 miles east of the town of State College. Penn's Cave has been offering boat tours since 1885. (Penn's Cave/PENN'S CAVE)

Dark. Cold. Complete and utter disorientation.

I was loving it.

About halfway through a boat tour of Penn’s Cave, a natural cavern in central Pennsylvania, guide James Madonna turned off the spotlight he’d been using to illuminate our space. I sat in the inky blackness, unable to make out even the cool and clammy hand in front of my face. I’d forgotten all about the higher-than-90-degree temperatures about 75 feet above us.

If you’re looking to beat the crushing summertime heat, you can’t do much better than a deep, dark cavern. The earth’s natural refrigeration generally keeps the temperature in these underground chambers in the 50s year-round. Penn’s Cave, about 14 miles east of the town of State College and one of a handful of caves that you can ride through in a boat, has been offering tours since 1885 — long before the advent of modern climate control.

A few minutes before the tour began, I descended the 48 steps to the mouth of the cavern. As the air turned crisp at the bottom, I slipped on my windbreaker, already questioning the wisdom of wearing shorts. I envied some of the warmer-dressed guests, until I realized that the whole point of this expedition was to cool down and let the 52-degree chill of the cave permeate my bones.

Marketing Director Terri Schleiden later told me that Penn’s Cave guides are issued uniforms that include a long-sleeved pullover and a jacket, although some of them conduct six or seven tours a day in short sleeves. Employees don’t necessarily recommend that visitors be that brave.

“The hooded sweatshirts are a bestseller here,” Schleiden said.

About 20 of us teetered into the long, narrow motorized boat that James would maneuver through the cavern for the 50-minute tour. As we distributed ourselves between two benches, the flat-bottom boat bobbed back and forth, unnerving a few of the passengers.

Only after we’d started the ride did James tell us that the water temperature is a downright frigid 38 degrees. Thankfully, the only victims to take the polar bear plunge are assorted electronic items belonging to clumsy visitors. By way of comfort, though, James cheekily reassured us that if we fell in, all we had to do was . . . stand up. It turns out that the water is only 3 to 5 feet deep.

As we glided into the cavern, the sparse sunlight illuminated the wispy clouds our breath was forming. I tightened my jacket against the damp and covered my legs with my messenger bag. It’s not a bad idea to cover your camera, too: More than a few water drops hit me from above (this, according to James, is good luck).

To start, James regaled us with some of the cavern’s impressive facts and figures. About 11 million gallons of spring-fed water pulse through it every day. The limestone that comprises the geological formation is about 500 million years old, while the cave itself is younger, only about 30 million years old.

Native Americans had been visiting — and even living in — Penn’s Cave before a pastor by the name of James Martin “discovered” it in 1795. With the cave entrance quickly shrinking from view, it wasn’t hard to imagine what those early explorers must have felt.

This being the 21st century, however, we had a few modern conveniences helping us in our journey, namely an engine and electric lights. James expert­­­ly navigated the cavern’s many turns, perfectly positioning himself to lean over and flip switches to illuminate its several rooms, including one lit in a series of changing colors.

He used a spotlight that he could detach from the front of the boat to point out noteworthy stalagmites and stalactites. It felt like a Rorschach test. That one, with a resemblance to the Abominable Snowman? Okay, maybe. But that other one, supposed to be the pope? Not seeing it. Still, the crowd oohed and aahed at the wonders that nature had slowly wrought, at a rate of about an inch every 300 to 500 years.

At the end of the cavern, we exited onto Lake Nitanee and into a blast of hot, humid air. Within seconds, I’d unzipped my jacket and started to pull it off. After a few minutes of looking for animals (there’s also a wildlife park on-site), we turned back toward the cavern. Even before we entered, I could feel the cool air emanating from the opening, creating a wind tunnel as we forged ahead.

On the return trip, James directed our attention to other limestone oddities that we hadn’t been able to see as well on the way in, such as a set of serrated stalactites reminiscent of shark teeth.

By the time we pulled back up to the dock, my nose and feet had gone slightly numb from the cold. When I reached the top of the entrance staircase, my glasses fogged up.

Sadly, the effects of the cave wore off quickly. A nearby bank’s electronic display emphasized the reason: 94 degrees.

The next day, I could have chosen from any number of other caverns for an additional subterranean fix. But I drove to Trough Creek State Park, about two hours from Penn’s Cave, to investigate its Ice Mine instead.

The story goes that some prospectors may have dug the mine shaft looking for iron ore. No luck on that count, but they did end up creating a nice little outdoor refrigerator where, the park says, ice can be found into the summer months.

A slow drive through the very pretty park brought me to the shaft, which, as I’d been sort of warned by an employee, was essentially a set of stairs leading to a small opening in the shaft wall.

About halfway down the 17­­ or so steps, the temperature dropped. It got even cooler closer to the hole. Perhaps it was my lack of a flashlight — the smartphone just wasn’t cutting it — but I couldn’t make out any ice. And though I can be daring sometimes, I have my limits, and feeling around in a dark hole in the middle of the wilderness is one of them.

A little deflated, I trudged up the stairs and paused when I reached the top, allowing my glasses to defog.

Then I ran right back down.