Weather is the driving force in deciding on a honeymoon locale. But it's not the only factor -- the number of tourists, activity availability, and changing rates all play a part in the destination puzzle.

Find out the best time to go to some of the most popular and exotic honeymoon spots.

Why: Top-notch weather, and if you love star-watching, it's the Caribbean haven for celebs in early January. If not, then go in late January.

Honeymoon must: Take a boat or hike over to Anse a Colombier Beach. It's the hardest to get to of Saint Barth's 14 beaches, so it's far more intimate than the rest.

Why: If you don't mind the heat, visiting the Argentine capital, Buenos Aires, in the middle of their summer offers honeymooners incredible deals, letting you afford five-star service on a three-star budget.

Honeymoon must: Step back into the 1940s for dinner as well as a truly authentic tango show at Esquina Carlos Gardel (from $170, esquinacarlosgardel.com.ar).

Why: The weather is perfectly calm, and the water temperature is ideal.

Honeymoon must: Walk up and down the pristine sandy beaches of Montego Bay, do some up-close snorkeling with the fishes at the underwater marine park at Cornwall Beach, then sample exotic Jamaican fare at the ever-popular Pier One Restaurant & Bar -- the menu changes with the season and the sea. Find an equally popular hotel in Montego Bay at theknot.com/honeymoons.

Why: Going at the tail-end of the high season won't save you money, but it might spare you a few tourists.

Honeymoon must: Don't miss the Mayan ruins at Caracol, a site that was once larger than Belize City. The towering pyramid called "Caana" rising above the trees is an awesome sight, and with the area still being excavated (those large mounds are actually structures that are still buried), one can only wonder what the city must have looked like at its peak.

Why: This month is just before the high season, so it may be pricier, but perfect honeymoon weather and fewer tourists make it worth every penny.

Honeymoon must: On the island of Santorini, dine in open-air taverns and restaurants next to the spectacular volcanic caldera. Local specialties, such as octopus in onion sauce and mussels with rice and raisins, will keep you coming back night after night.

Why: The rates are cheaper than in July and August (which are their two driest and usually busiest months), yet the gorgeous weather is still the same: cool and dry.

Honeymoon must: Stroll through Mahe's more-than-a-century-old botanic gardens filled with nearly every exotic tree, flower, and plant on the island. Or leave the island altogether on a chartered yacht to see Aldabra, an atoll ring of four coral islands home to over 150,000 giant tortoises.

Why: Even though it's roughly 79 degrees year-round, July is when the locals have their Heivai Tahiti festival, a month-long celebration of Tahitian culture.

Honeymoon must: Surround yourself with reef sharks, sea turtles, and tropical fish at the Lagoonarium viewing room, or be adventurous and try a safari trip to the center of the island.

Why: It's wintertime, which means the area is drier and the lodging is modestly affordable.

Honeymoon must: Hit the beach. Try the sandy strands of Grand Bay, Pereybere, and Cap Malheureux on the northern coast; Belle Mare on the east coast; and Blue Bay on the south coast.

Why: With the summer crowds gone and the weather a bit cooler, you'll soak up Spanish culture with your personal space intact.

Honeymoon must: In Barcelona, check out the unbelievable architecture of Antoni Gaudi, who blessed his many creations with breathtaking curves, colors and asymmetrical oddities.

Why: The charm of Italy's Old World hospitality may be timeless, but October falls within Northern Italy's wine harvest season. That means plenty of wine events, tastings, and unveilings of new vintages.

Honeymoon must: No honeymoon in Venice is complete without a gondola ride so cuddle up and glide through the enchanting canals. It will run you from $75 to $100 for up to a 50-minute ride.

Why: Beautiful weather in the mid- to upper-70s on average creates the perfect backdrop for your Mexican getaway.

Honeymoon musts: Take a boat over to Lover's Beach for a picnic lunch, some sand under your toes, and panoramic views of the Pacific Ocean.

Why: Going the weeks before Christmas -- the only real off-season for Sin City -- offers more intimate excitement thanks to fewer tourists.

Honeymoon must: Recapture your wedding day butterflies with a tandem skydive and a five-to-seven-minute parachute descent over Vegas ($249 per person, vegasextremeskydiving.com).