Travel is an investment, and most travelers want to make sure they get a fair return. Factors like weather can wreak havoc on vacation plans. That's why so many of us are willing to put up with crowds and high-season prices in return for the best possible odds of good weather. After all, the whole point of going to the Caribbean in winter is to experience warmth and sunshine, and the main reason to go to the Rockies during the winter is snowfall and ideal ski conditions.

What if there were a way to experience ideal (or near ideal) conditions without the crowds? Many destinations have a kind of secret season when you can avoid crowds and high prices without sacrificing sunshine (or snowfall).

An open secret for savvy travelers

Travel agents and insiders call this time of year "shoulder season." It occurs directly before or after the peak travel season or major holidays. These weeks and months are defined by mostly pleasant weather, uncrowded attractions and low prices. Shoulder season benefits can be especially pronounced in popular travel destinations such as the Caribbean, South Pacific or Western Europe, but every place that has a peak tourism season should have a shoulder season just before and/or afterwards.

So when is shoulder season?

In most Northern Hemisphere destinations, the main shoulder season falls between September and November. This is after the traditional summer vacation but before the holidays and snowbird season. Beach and ski destinations often have a second shoulder season in late April and early May (after spring break but before summer vacation).

The exact dates vary, but every destination has a "tell." When hotel rates and airfares start falling (and there's no other obvious reason for the discounts), this is a sign of the start of shoulder season.

Managing weather risks

Caribbean aficionados are often quick to point out that September, October and early November are still within hurricane season. This is true, and it could be a potential risk for travelers, but savvy West Indies and Eastern Mexico visitors can use strategies like buying trip insurance or visiting places like Aruba that are outside of Hurricane Alley. In many cases, there's a sweet spot between storm season and the start of peak travel season. Discounts in hot spots like Cancun or elsewhere on the Riviera Maya can reach 50 percent if you travel in late November, but before Thanksgiving.

How much can you save?

According to online travel agents and booking sites, the savings can be significant. Shoulder season discounts vary depending on the destination. Variables such as the success of the previous peak season and projected bookings for the coming year could influence prices. The more a destination needs your business, the lower the rates and airfares should drop during shoulder season. In general, you can expect average savings of 20 to 30 percent compared to peak prices.

Enlist the help of a travel agent

If you want to measure these discounts for yourself, you can search for rates for a hypothetical high season vacation (say, in Cancun in December or early March) and compare these prices with a late October stay. Another option is to contact a travel agent (yes, they still exist). They should be aware of the best shoulder season dates for your chosen destination.

The St. Thomas Virgin Islands Carnival Parade takes place in April or May each year, when tourists are less likely to be around. Kendra Nielsen/Shutterstock.com

When the tourists are away, the locals play

This leads to another attractive aspect of shoulder season: the local angle. In destinations that rely heavily on tourism, shoulder season is when local people come out to celebrate. This can be an attractive dynamic for people who want to avoid the usual tourist scene and mingle with locals who they might not otherwise meet.

Some festivals fall during shoulder season. For example, Carnival on Saint Thomas, in the U.S.Virgin Islands, is in April and May, and Barbados' Crop Over festival takes place in April. Destinations often promote these events, so there may be more demand than during other shoulder season weeks, but you'll avoid the spring break crowds.

What about cruises?

Cruisers may find shoulder season deals more difficult to obtain. Savvy cruise firms may simply move ships to different high-demand routes rather than lowering their prices. Some cruise lines continue to operate. Caribbean cruises are at their lowest rates in October and November. An autumn river cruise in Europe could also bring similar deals, though the saving might be moderated by demand from fall color seekers. Instead of lowering prices, some lines may offer other promotions such as two-for-one tickets or premium cabins for the price of regular cabins.

Sometimes you have to learn to deal with drawbacks. (You can get all the information about a destination's weather patterns so you can decide if a drawback is really a drawback.) In May in Southeast Asia, for example, it rains daily. However, the rains are predictable, occurring like clockwork in the morning or afternoon (depending on your location) and then giving way to heat and sun. You won't be sidelined for more than an hour or two.

If your schedule allows it, traveling during shoulder season can bring significant savings, more authentic experiences and fewer crowded attractions.