(MONEY Magazine) – Almost every popular vacation destination has a secret season. It's the little-known sweet spot between peak travel season, when a place is overrun with tourists and sky-high prices, and the off-season, when rates are rock bottom but the weather's lousy and there's nothing much to do. It's those few weeks a year when you can enjoy good weather and the best of an area's attractions, when you can soak up local culture without being besieged by hordes of fellow travelers—all for 15% to 50% off peak-season rates.

Sure, there are sometimes trade-offs. You may have to pull on a sweater at night walking on the beach. Or take a longer siesta to wait out a burst of rain. But for most locales, you'll be pleasantly surprised at just how little you have to give up and how far your vacation dollars go.

The following secret-season guide highlights the very best of these deals, based on the recommendations of more than 40 top-rated travel experts. We hope you will use it to plan your next great vacation—and leave the crowds and high prices behind.

Caribbean cruises

WHEN The first three weeks in December

WHY You'll find the best combination of great weather, thin crowds and compelling deals on Caribbean cruises if you ship off when most people are packing the malls back home for last-minute holiday shopping. "We hear a lot of 'I don't want to be away from home then,'" says agent Judy Lucas of Concierge Cruises & Tours in Tucson. You'll get plenty of sun, temperatures in the 70s and 80s, and you'll avoid hurricane season, which runs from June 1 to Nov. 30. Plus, if you haven't bought all of your own gifts yet, you can stop in to shop at ports of call, fully decorated for the holiday season.

THE DEAL Cruise-ship fares are 20% to 40% off winter to mid-spring rates. For example, an outside stateroom on a seven-day Holland America cruise to the Eastern Caribbean, with stops in the Bahamas, St. Thomas and other ports, costs $1,681 for a trip that leaves Dec. 11, compared with $2,189 for the same room on a Dec. 23 departure.

Rome

WHEN January and February

WHY Chilly weather keeps most tourists away from Europe in winter. But the temperatures in Rome, typically in the mid- to high 50s at this time of year, are about 15°F warmer than in most of the rest of the continent. True, that's probably still too cool to enjoy a glass of Chianti outdoors at one of the Via Veneto's many sidewalk cafés. But it's perfectly comfortable for visiting the city's many historical attractions, such as the Roman ruins and Spanish Steps, as well as the bountiful museums, galleries, monuments and churches, without the crowds of tourists that can detract from the experience in the peak summer and early fall travel times. A few restaurateurs and hoteliers may shutter their businesses for the winter months, but the ones that remain open will offer discounts, and "they are thrilled to see you," says Victoria Goyet of Endless Beginnings Tours in San Diego. "In September, people are grouchy."

THE DEAL Air fares are dirt cheap in the winter: $427 on Delta for a round-trip ticket from New York City in late January and early February vs. $788 for the exact same flights during the Easter holiday. You'll get big savings on hotels too. For example, the recently renovated Hotel Fontanella Borghese, a 17th-century hotel that is just steps away from the Borghese Palace, Spanish Steps and other important monuments, offers antique-furnished rooms for two, including breakfast, for $185 a night, compared with $225 to $250 in high season. If you prefer luxury to quaint and charming, the rate for an eight-night January and February stay at the upscale St. Regis Grand is $348 a night; over Easter, it's $497 a night.

Disney World, Florida

WHEN The first three weeks of December

WHY The lull between Thanksgiving and Christmas offers near-perfect conditions in Disney World in Orlando: sunny, spring-like weather and some of the shortest lines in the park all year. What would normally be a two-hour wait for popular rides like Space Mountain in spring or summer, for example, shrinks to less than 15 minutes. Early December daytime temperatures are typically in the mid- to high 70s—ideal for traipsing around the park, particularly compared with summer, when the temperature is in the 90s and the humidity is near 100%. You'll find little traffic getting to and from the park, and you can enjoy Mickey's Very Merry Christmas show amid the glow of holiday lights and decorations.

THE DEAL "Disney doesn't really discount," warns agent Renee Coon of North Coast Travel in Erie, Pa. But while you may not find deals in the park itself or at Disney-owned properties, you can get up to 30% off at nearby hotels. For example, the Buena Vista Suites, just a mile away from Disney's gates, offers a two-room suite with a kitchenette and free buffet breakfast for $89 to $99 a night in early December vs. $149 during peak holiday, summer and school break travel season. You should be able to get a break on air fares too, especially with so many discount carriers serving Florida.

INSIDER'S TIP For hotel deals and advice on navigating the parks, visit mousesavers.com.

Napa Valley, Calif.

WHEN February and March

WHY Napa in winter offers all the pleasures of wine country during the peak summer season with one notable exception: You won't see the actual grapes. But while the vines will be bare, wine aficionados can still tour both big and boutique wineries, attend seminars and tastings to refine their palates, and even score a chance to meet the winemakers in person (which typically isn't an option during the busy harvest months). The scenery is still lovely—the hills are blanketed with wildflowers and the mustard plants that cover the fields are in full bloom—while the weather is temperate (albeit rainy), with highs reaching the mid- to upper 60s during the day. A bonus: The Napa Valley Mustard Festival, which runs from Jan. 29 to April 9, features dinners prepared by award-winning chefs, wine tastings and, of course, mustard recipe competitions.

THE DEAL Hotel rates and package deals are as much as 40% lower than in peak season. For instance, the four-diamond Villagio Inn & Spa in Yountville offers a Sunday-through-Thursday Spa Escape package that includes lodging, a bottle of wine, a champagne breakfast each morning and two 50-minute spa treatments for $350 a night in the winter vs. $500 in peak season. If a quiet country inn suits your taste and wallet better, the Wine Country Inn in St. Helena (18 miles from downtown Napa), offers antique-furnished rooms, free breakfast and afternoon wine socials for $185 a night vs. $220 in high season.

The Riviera Maya in Mexico

WHEN Late April and May

WHY With its long stretches of white beaches, translucent waters and proximity to the U.S. (only about an hour and a half flight from Miami), the Riviera Maya, just south of Cancún, attracts thousands of honeymooners, families, and vacationing students each year. Trouble is, if you go during the peak spring break and summer seasons, the endless lines at restaurants and crowds of English-speaking tourists will make you feel as if you haven't left home. But the months after college kids have headed back to school and before the beginning of summer family travel offer a lull when you'll find perfect beach weather, little rain and far fewer crowds at spectacular Mayan ruins like Chichén Itzá.

THE DEAL Hotels are about 25% off peak rates. At the Shangri-La Caribe in Playa del Carmen, an ocean-view room costs $135 a night after April 16 vs. $180 in the winter. You'll also find good packages. For instance, the Viva Wyndham Maya Resort has all-inclusive deals (food, drink, lodging, activities and taxes) starting at $180 a night in May, down from $244 in high season.

INSIDER'S TIP For the best prices, consider using a charter company like Apple Vacations, which offers four-night, all-inclusive packages to the Riviera Maya that include flights, hotel, food and drink for as little as $700 per person—only slightly more than you might pay during peak season for a flight alone.

The Caribbean

WHEN April, May, June

WHY Stay at a luxury hotel for up to half off the high-season price after winter vacationers head home, and you'll have the beach practically to yourself. Sure, you won't have the cachet of a tan in February, but the weather is practically the same—78°F to 88°F during the day—though it will be a bit more humid, so it will feel hotter.

THE DEAL Hotel rates drop 20% to 50% after April 15. For example, a garden cottage with daily breakfast at the Hotel Le Village St. Jean on St. Barthelemy goes for $180 a night in spring; that same deal will cost you $270 a night in the winter. Meanwhile, rooms at the ultraluxurious Four Seasons Nevis start at $450, compared with $625 a night in the winter. In June the rate drops even further, to $325 a night.

INSIDER'S TIP Many islands hold their music festivals, carnivals and other events outside of peak season. In Barbados, for example, enjoy the Celtic Festival, GospelFest and an International Folk Festival, all in May.

Arizona

WHEN May

WHY Most travelers steer clear of the Arizona heat after mid-April. Granted, peak daytime temperatures in May are hot—about 90°F in southern cities like Tucson—but not nearly as scorching as summer, when the mercury frequently tops 100°F. Moreover, temperatures stay in the 60s and 70s until mid-morning, so early risers can still comfortably enjoy outdoor activities like biking and golf. May is also a prime month for bird watching in southeastern Arizona, as millions of songbirds fly north during spring migration. Or you can take a trip to the Grand Canyon, where the mid-60s daytime weather is perfect for hiking.

THE DEAL Many Arizona hotels start low-season rates in the first two weeks of May, with prices 30% to 40% lower than in winter. For instance, the Pointe South Mountain Resort in Phoenix, which has its own water park and an eight-story water slide, was recently offering rooms for $179 vs. $259 a night in high season.

INSIDER'S TIP Competition from low-cost airlines has driven down fares to Las Vegas, a common jumping-off point for Grand Canyon tours, as much as 70% year round recently.

Patagonia, Chile and Argentina

WHEN March

WHY In the Southern Hemisphere, the seasons are reversed. So just as we're slogging through the early spring slush, gorgeous fall foliage dots the landscape of southern Chile and Argentina. Tourists head to Patagonia for some of the most scenic natural beauty in the world—gigantic glaciers, dense forests and ice fields dotted with penguins. Winter is high season (when it's summer there), but in March the weather is still temperate, and fewer tourists will stand between you and the region's remote, unspoiled beauty.

THE DEAL Patagonia is never a low-cost destination—the air fare, the food and even the local guides cost a pretty penny, no matter when you go. But with the right timing, you can at least stay pretty cheaply—most hotels discount rooms 30% to 40% starting in March. For example, double rooms at the Mirador del Payne near Torres del Paine National Park in Chile go for $90 a night, down from $152.

INSIDER'S TIP You'll also find good travel deals in late October and early November (which is spring in Patagonia). Plus you'll get to see the spring wildflowers blooming.

San Juan Islands, Wash.

WHEN June

WHY Throngs of tourists head to the San Juan islands in Washington for whale watching, hiking and sea kayaking each year, but most wait until July, since the infamous Pacific Northwest spring rains often drag on until mid-June. But in reality, June is only marginally wetter than July, and temperatures in both months range from the mid-60s to the 70s, with 16 full hours of daylight. Plus, you'll be far more likely to spot whales, since the orcas follow the early-summer salmon migration and swim nearest to the islands in June.

THE DEAL Hotel prices are 20% to 30% lower than in the summer season. Before June 17, for example, the luxurious Resort at Deer Harbor on Orcas Island has deluxe cottages for $209 a night, compared with $279 during the summer season. At the moderately priced Cascade Harbor Inn, where all rooms have balconies overlooking the water, a room with two queen beds is $104 through June 30, compared with $149 in late summer; or you can upgrade to a family-size suite with a full kitchen and fireplace for $209 a night vs. $299 after July 1.

Belize

WHEN May to July

WHY Fish fanatics flock to Belize—considered second only to Australia's Great Barrier Reef for diving and snorkeling—in the winter. But the weather in this tiny country is much the same year round: hot (mid- to high 80s) and humid. The government prohibits high-rise construction, so the country's small, independent hotels fill up fast in the winter, when vacationers en masse are fleeing the cold weather back home. Go in the summer and you'll find a room easier to book. The rainy season runs from April through November, but May, June and July are the driest months during that period; even if it does rain, it's usually just a short late-afternoon or evening shower.

THE DEAL Hotel rates are up to 30% lower than in peak season. A suite at the Rum Point Inn in Placencia, on one of the area's prettiest stretches of beach, goes for $129 a night in summer vs. $189 in winter. Air fares are cheaper too: A round-trip ticket from Denver to Belize is $600 to $1,000 in the winter vs. about $350 in the summer.

INSIDER'S TIP Stay on the north side of the country, which gets less rain.

Rocky Mountains

WHEN July

WHY If you are interested in visiting the area only to schuss down a hill on skis, your options at this time of year are extremely limited (glacier skiing is it). But if you're looking to pursue other rugged outdoor activities amid spectacular scenery, the Rockies in July are ideal. You can go mountain biking, white-water rafting and hiking (or for the more adventurous, heli-hiking) while enjoying the sights of wildflowers in bloom and roaming wildlife.

THE DEAL You'll find huge savings on hotel room rates. At the Stein Eriksen Lodge at posh Deer Valley Resort in Park City, Utah, the summer rate for a deluxe bedroom is $205, compared with $695 in the peak holiday periods. Jackson Hole's Teton Mountain Lodge offers a golf-and-stay package, featuring one night in a deluxe room and one round of golf for two at a Robert Trent Jones Jr.-designed golf course, starting at $189 vs. $299 a month earlier.

INSIDER'S TIP If it's skiing or bust, go in January (except Martin Luther King Day weekend), during the lull between the masses of holiday tourists and mid-winter escape travelers. With fewer crowds, lodging-and-lift packages may be as much as 30% cheaper.

Paris

WHEN August

WHY Most Europeans are on holiday, packed in like sardines at the beach resorts, leaving major Western European cities relatively empty—perfect for visiting the tourist attractions without crowds and for scoring deals. Paris is an ideal choice because, despite last year's uncharacteristic 100°F heat, it typically boasts pleasant August weather: The average high is 75°F, compared with 87°F in Rome. Some restaurant and shop proprietors may be on vacation too, but plenty will remain open. Among places to stay, you'll find the deepest discounts at luxury hotels in August, since there will be virtually no business travelers in town, leaving plenty of room at more upscale lodgings.

THE DEAL You can get hotel rates as much as 40% off their peak. For instance, the Hotel Sully Saint-Germain, in the heart of the Latin Quarter, has small but charmingly furnished rooms that go for $150 a night in August, compared with $180 to $210 a night in the spring.

Hawaii

WHEN September to early November

WHY There is no official off- or shoulder season for Hawaii, where the weather is fabulous year round. But crowds do thin out when school is in session and before the Thanksgiving and December holidays, so you'll find lower hotel prices and cheaper air fares if you travel in the fall.

THE DEAL Discounts on hotel rooms range from 10% to 35%. Hotels are also likely to throw in perks such as single and double room upgrades, free nights and car rentals. For example, if you stay four nights at the newly renovated Fairmont Orchid on Mauna Lani for $299 a night, you can get upgraded to an ocean-view room, with breakfast included and a fifth night free. Stay in a garden-view room at the Kaanapali Beach Hotel on a gorgeous stretch of beach in Maui for $205 a night and get a rental car for each night of your stay. Flights are a little less too: about $700 round trip from the East Coast and $600 from Chicago, both about $100 cheaper than in peak season.

Greece

WHEN September to mid-October

WHY If you've got a post-Olympic craving to visit the Greek islands, wait until fall and you'll have them practically to yourself. The number of tourists drops dramatically after the first week of September, when student travelers are back in school and summer vacation crowds disappear. As a result, hotels begin reducing prices in early to mid-September, even though the weather is still balmy (80s during the day and 70s in the evening) and the water remains comfortable for swimming, with ocean temperatures averaging 72°F.

THE DEAL You won't get much of a break on air fares, but you can get up to 50% off on hotel rooms. On the island of Crete, for instance, the Grecotel Creta Palace hotel, where many of the Olympic swimmers stayed, charges $325 a night in the summer. But prices for a bungalow on the beach drop to $180 a night in September and $150 a night in October.

INSIDER'S TIP For an even better value any time of year, stay on an island that's not as well known to Western tourists. Paros and Naxos, a hydrofoil ride away from popular Santorini, have beautiful beaches and aren't as built up as some of the more popular islands.

Alaska

WHEN September

WHY Head to Alaska in the fall and you'll be treated to sights that the summer crowds never see, including spectacular fall foliage and wildlife preparing for winter. You'll also have a better chance of seeing the aurora borealis, the atmospheric phenomenon that causes a diffuse glow and streams of colorful light to appear across the polar sky. Temperatures will be comfortable but noticeably cooler than their summer peak, with highs only reaching the mid-50s, compared with about 70°F in July. There will be less sunshine too (13 hours, compared with 21 hours in June), but still enough daylight to enjoy traditional Alaskan tourist activities, such as wildlife and glacier tours, and kayaking and white-water rafting excursions.

THE DEAL Hotel rates are up to 30% off peak summer-season rates. Anchorage's Hotel Captain Cook, which boasts views of Mount McKinley, costs $145 a night in mid-September, compared with $245 a night in July. At the more rustic Denali Cabins, just a few miles from Denali National Park, you can stay in individual cedar cabins for $119 a night, compared with $179 in summer.

Quebec

WHEN September and October

WHY Instead of spending your entire fall-foliage weekend stuck in traffic on the highways of New England, venture a bit farther north to Quebec. Besides checking out Canadian maples ablaze with color (peak: early to mid-October), leaf peepers will also get to witness hundreds of snow geese stopping over the St. Lawrence River on their way south for the winter. You'll get crisp fall weather (average high in October: 52°F) and substantial savings on the exchange rate. But you will definitely have a longer drive: Mont Tremblant in the Laurentian Mountains, for example, is about four hours north of Burlington, Vt. While in town, check out Mont Tremblant's Symphony of Colours, a festival that features concerts, wine and game culinary events, plus showcases of local artisans, and runs from Sept. 11 through Oct. 31.

THE DEAL Hoteliers drop rates as much as 50% before the busy winter ski months. At the five-star Le Westin resort in Mont Tremblant, you can get a room with a gas fireplace, kitchenette and balcony for $154 for a Saturday-night stay in October; at the equally luxe White Barn Inn in Kennebunkport, Maine, comparable rooms go for $255.

BONUS TIP If you're not into leaf season but want to check out Montreal's old-European vibe, wait until November. Expect some slush and average highs of 41°F, which is cold, but not nearly as cold as December through February (when you're lucky if the temperature gets out of the 20s). You also get to see the city decked out in its holiday finery. On Nov. 17, Montreal puts up its monthlong annual Victorian Christmas exhibit, which captures how the city looked in 1862. Hotel rates will be well off summer-season highs too.