"Hot vax summer" is upon us. And one market in particular is already feeling the heat: vacation rentals.

If you're looking to travel this summer but haven't locked down a beachfront rental in Cape Cod or the Outer Banks just yet, you may be too late.

As coronavirus-vaccination needles meet American arms and travel restrictions ease up, the general outlook on the domestic travel industry shines ever brighter. But even as hotels start to fill up, many Americans may feel more comfortable in a space they can control, such as a rental home.

The search for rental properties has been ramping up for months. HomeToGo, a rental search engine, found that travelers were already looking for summer escapes in February, with searches up 27% year over year. In February 2020, the pandemic hadn't yet overwhelmed the US, which indicates that this newfound hunger to get away is reaching new heights.

Now, with Memorial Day looming, there's barely any rental inventory left in a number premier beach destinations across the country this summer.

The prevalence of remote work has driven hordes of well-to-do urban dwellers out of major cities, leading many to settle in vacation towns for the long haul, either buying property or booking much longer vacations than usual.

The rental platform Vrbo found that users are 75% more likely to book a stay of at least seven nights this summer — and 33% less likely to book a three-night stay, a once typical timeframe for a quick summer getaway.

The shift toward longer stays has pushed rental prices to never-before-seen highs and inventory to record lows. (It's comparable to the sales market, where limited supply and outsize demand have led to higher prices.)

Brokers, rental platforms, and management companies are already reporting an exciting summer season at beachy destinations across the country.

We found out what the scene is like in four particularly hot spots.

Summer-rental rates in the Hamptons' string of ritzy beach towns are "at an all-time high," while "inventory is at an all-time low," said James Keogh, a broker at Douglas Elliman.

A Memorial Day to Labor Day rental in the Hamptons can range from $75,000 to $750,000, Keogh said, adding that the median range is a narrower — but still pricey — $75,000 to $100,000. Keogh estimated that prices have gone up about 40%.

There's not much left: Most vacationers locked down their summer properties between January and February, he said. "By March, almost everything was gone."

The lack of available homes to rent has increased competition over each one, pushing anything with six bedrooms over the $100,000 mark, he said.

Historically, Keogh said, rentals that fetch north of $100,000 sit "south of the highway," referencing the cluster of streets tucked between Route 27, the major east-west thoroughfare that bisects the Hamptons, and the Atlantic Ocean. Those properties closest to the beach are the most coveted — and expensive. But now, with such little inventory for rent, the $100,000-plus price tags can be found north of the highway, too.

The most expensive summer deals Keogh's team handled this year were a $500,000 rental in East Hampton and a similarly priced one in Montauk. These homes — which are often oceanfront — command such dear prices because they come with a laundry list of perks, such as steam showers, wine storage, tennis courts, and finished basements with media rooms.

For the past decade, most vacationers opted for short-term stays, Keogh said, looking to rent a place for two weeks. Now, "it's become much more long term," he added. Renters are planning to stay "out East" for the whole summer season — Memorial Day through Labor Day.

Other renters make their stays even longer than that, looking to reside beachside for between three and four months, Keogh said.

And others are going all-in on the East End, he added — opting for a full year.

Martha's Vineyard, the Massachusetts island just south of Cape Cod, is perhaps the most exclusive of the Northeast's summer hideaways.

Home to six charming towns, rural farmland, and pristine beaches, the enclave has attracted notable residents and visitors. Figures such as Oprah Winfrey and Bill Gates have vacationed there. Accessible only by boat or air, the island's reputation for privacy has long attracted the likes of presidents, too: Jackie Kennedy spent summers there (in a $65 million mansion, no less). And in 2019, the Obamas bought a $12 million property for seasonal getaways.

Now, the go-to getaway for New England's wealthiest is seeing a glut of reservations from pandemic-weary vacationers booking their summer holidays.

"There's huge desire to be out here," said Alyssa Halisky, a Sotheby's agent on Martha's Vineyard. She added that finding a rental is "so much harder now than in 2019."

Just a few years ago, island homeowners trying to fill their houses with renters for the entire summer often couldn't line up a tenant for every week. Today, that isn't the case. "It's a completely different market now," Halisky said, one with "very limited inventory."

For a five-bedroom house with a pool, rental pricing can start at $20,000 or $30,000 a week, Halisky said, and premium beachfront properties can fetch as much as $50,000 a week.

Previously, typical visitors wanted to spend just one week on the island in July and August, but now Halisky's getting calls for stays outside of the traditional season, as early as May through as late as October. And people are starting to stay longer than a week, she said. The average family that used to spend a week on Martha's Vineyard now prefers to rent for one to two months.

"I wouldn't say it's too late to rent," Halisky said. "But there aren't a lot of options."

Vacationers dream of a Hawaiian getaway, but the reality is that there aren't many options left — and the ones left will cost you.

Summer in the Aloha State will be exceptionally busy, said Matt Beall, the CEO and principal broker of the statewide brokerage Hawai'i Life. The brokerage's rental inventory is almost fully booked for the summer.

The brokerage, which operates 270 vacation rentals and 375 long-term rentals on popular islands such as Kauai and Maui priced from $200 to more than $10,000 per night, has already recorded the highest occupancy rates on record.

Hawai'i Life found that its average daily rates for June 2021 increased by 24% from the same period 2019, from $567 to $704 a night.

"It definitely started on the high end of the market," Beall said. "All of the nicest homes that we rent booked first."

To help make up for losses from regular tourism, Hawaii has tried to position itself as an ideal location for remote workers staying on the islands for longer stints. But now that travel restrictions are loosening, the state is bracing for even more arrivals.

The volume of rental bookings picked up substantially in Kauai on April 5, Beall said, after the island was allowed into Hawaii's Safe Travels Program, which means visitors can head there without quarantining as long as they test negative for COVID-19 within 72 hours of traveling.

Others are committing to Hawaii property by purchasing it. Many high-end properties in Kauai, for example, have been bought outright during the pandemic. Take Facebook CEO Mark Zuckerberg's latest addition to his massive real-estate portfolio: He shelled out $53 million for 600 acres of land on Kauai's North Shore.

Vacationers making a beeline for the area, Beall said, largely come from the West Coast, as well as places such as Texas, Colorado, and New York. Competition from all the out-of-staters can be fierce.

"If you're looking for a vacation rental on Kauai right now, you're going to have a very difficult time," Beall said.

North Carolina's once low-key beach destination has boomed in popularity recently thanks to easy access from East Coast cities, affordable rentals, and, yes, a beloved Netflix show with the same name. The area, which was once a string of barrier islands with dilapidated single-story cottages, now boasts extravagant mansions, gourmet restaurants, and ritzy private clubs.

The Outer Banks' once quiet towns are some of the most popular spots vacationers are eyeing this summer. In fact, the 130-mile stretch is the No. 1 destination in the country for stays of at least seven nights this summer, Vrbo said. And 90% of the Vrbo rentals there are booked through July.

What happened next is no shocker: That demand has pushed up prices. The New York Times' Sarah Firshein reported that rates for the vacation homes of Twiddy & Company, a local hospitality firm that manages 1,000 properties in the Outer Banks region, have jumped by 8%. Desirable beach houses that were renting at a weekly rate of $8,406 in 2019 are now renting for $9,152.

Also, some people have purchased — for their personal use — properties that served as rentals in prior years. So there are fewer homes available to rent this summer, which ramps up competition over the remaining inventory.

"I would say maybe about 15% of my buyers have decided not to rent out the houses," said Edith Rowe, a native of the area who has brokered deals there for 21 years. That figure is "higher than it was in the past," she said, "mostly because everybody can work from home and school is remote."

Another factor that is worsening the inventory crunch: Some of last year's summer vacationers never left, so hopeful 2021 travelers have even fewer options.

That housing shortage is compounding a labor shortage in the area, too. Owners of properties typically rented out to seasonal employees at restaurants and other leisure and entertainment venues have found that they can earn more by listing the digs to tourists on Airbnb.

That leaves workers, including college students and those abroad, priced out. As a result, Outer Banks businesses report that they are understaffed and overwhelmed.

Expect those tensions to repeat themselves across American beach towns this summer.

Taken together, it means that trying to get in on the vacation-rental rush right now could mean overpaying to hunker down in a tiny bungalow in a hot spot that's overrun with tourists and stretched on service.

Far from the summer break of your dreams, right?