Punta Arenas whale watching, among the glaciers

After 1.5 hours of sailing comes Cabo Froward, the headland where the American continent ends, and the boat passes it for 30 minutes. Then the channels narrow, the mountains close in and you enter the Francisco Coloane Marine Park, where the boat spends 3 hours searching for whales and watching wildlife.

The afternoon brings another 2 hours with marine life, then a long sail of 3.5 hours back through the strait and the bus to town. Lunch and a snack are included, and you are back where you started at the end of the day, tired, windswept and usually full of photographs.

What they eat is local: krill, lobster krill and Fuegian sprat. Where seabirds gather over the water, food is often close to the surface, and the guides on board watch for exactly those signs while they scan for a blow.

The same animals return year after year. A three-summer study found a return rate of 78.9%, and the number of whales using the area was estimated at 72 in 2008/2009 and 93 in 2016/2017. Each whale is known by the pattern on the underside of its tail, which researchers use like a fingerprint.

The whales come up in almost every review, often with surprise at how many there were and how close they came to the boat. Several guests also mention sea lions, penguins, dolphins and the glacier, and one remembers drinking with glacier ice at the foot of the ice wall.

The food and the warm drinks are part of the story too. Guests mention hot drinks, soups and lunch on board, a heated cabin to retreat to, and a long day that felt well organized from the early check-in to the ride home.

In the austral winter the population breeds far to the north, along the coasts from northern Peru to Panama and Costa Rica. Some whales travel between the strait and Colombia, a minimum distance of 6,650 to 7,000 km each way.

The booked listing does not name its months, so check the dates offered in its booking calendar. December and January also bring the longest days: at mid-December the sun is above the horizon for 16.9 hrs in Punta Arenas.

Seasickness is the most common complaint, especially on the morning crossing. The CDC advises taking motion sickness medication before you set off rather than after symptoms begin. Standing outside and watching the horizon helps, and the boat's cabin is a warm place to rest between sightings.

Rain falls in every month instead of arriving in a single wet season. Even in January, the warmest month, the average high in Punta Arenas is 15.3 °C, with 8 days of at least 1 mm of rain. Expect to see sun, cloud and showers in the same day.

Book the whale day early in your stay. If the operator changes a date for the weather, you still have days left to go out again, and you will not be racing to catch a flight on the evening of a long day at sea.

Hotel pickup is not included, so plan how you reach the starting point at José Nogueira 1255. Staying near the center makes the early start easy, and a taxi is the simplest option if you are further out.

Use a fast shutter speed and burst mode, and keep both eyes open so you can see the next blow coming. A zoom lens helps, because boats keep at least 100 meters from large whales under Chilean rules. Sometimes the whales come closer on their own, so do not pack the wide lens away.

The landscape deserves pictures too: glaciers, waterfalls and forested slopes line the channels. Keep a cloth to wipe spray off the lens, a spare battery in a warm pocket and a dry bag for the phone.

Start with a thermal base layer, add fleece or wool and finish with a windproof, waterproof jacket. A hat, gloves and a scarf make the biggest difference on deck, where wind and spray make the air feel colder than it is.

Sunglasses are worth bringing too, because light off the water and the ice can be bright. Keep a small bag with your essentials so you can move quickly when someone shouts that a whale has surfaced.

Use the guides. They know where the whales tend to feed, which birds are following the boat and what the glaciers are called. Ask about the research on the Strait of Magellan humpbacks; there is a lot to tell.

The crew also keeps an eye on safety. Follow their instructions about life jackets and where to stand on deck, especially when the boat is moving fast or the sea is rough.

The municipal cemetery, a National Monument since 2012, is one of the city's best-loved sights. For a rainy day, the Museo Regional de Magallanes keeps eight rooms as the Braun-Menéndez family lived in them.

If you have another day, the penguin colony on Isla Magdalena lies 35 km northeast of the city and is open to visits from October to April. It makes a perfect half-day partner to the whale trip.

It is less suited to anyone who suffers badly from seasickness, small children who struggle with long days, or travelers short on time. A shorter dolphin trip near town lasts 3.5 hours and may be the better choice for them.

No one can promise a sighting, and the listing does not. Whales are wild animals, and the weather has the final word on the strait. Go in the peak months, give yourself a spare day, and enjoy the journey as much as the destination.