Rain. Falling — torrentially — and flooding the boat. And then it’s over. My feet are wet. My trousers are wet. The children are wet. We are all, completely, utterly soaked through. No complaints though; we’ll wait for the passing sheets of rain to pitter patter out. This is rainy season in Costa Rica, officially from May to November (though I’m convinced it’s longer) and we’re lucky to be seeing the country in full bloom, phosphorescent green, buzzing, thriving, pulsing with life. Welcome to the rainforest. The giveaway is in the name. Walls of green and, at times, walls of water. It also partly explains why Costa Rica is renowned for packing around 5% of the world’s bio diversity, despite accounting for only 0.03% of the earth’s surface.

Water literally brings with it the building blocks of life. And Costa Rica is unique in that it has an ocean — the Pacific — and the Caribbean sea relatively close to each other. Classified as tropical because of its close proximity to the equator, it doesn’t really have a winter period. The sun shines here throughout the year. Between the rain that is. We’re on an open-roof boat (crazy, I know) on a nature tour, travelling through the Tortuguero National Park with our always-smiling guide, German Rojas, a very keen and infectious birdwatcher, who stands at the fore of the boat, binoculars in hand, he’s one of two travel directors supplied by our specialist Costa Rica operator, Trafalgar.

The canals and lagoons here are teeming with life: agile howler monkeys, white-faced capuchins, scary-looking caimans, numerous exotic bird species, rare ocelots, river otters and manatees. Yet in the rain, we struggle to see them. We’ve been given thick, plastic ponchos in electric blue; impenetrable and indispensable in a way no brand-name jacket can live up to. But less than 25 minutes in, we start to hear the animals and the sun arrives almost as quickly as the rain stops. In the dry, we can differentiate green macaw, tiger heron, the kooky black-and-white piano bird, woodpecker, parrots (in a pair), vulture, caiman and basilisk. We pause to seek out the grey potoo bird, posing as part of the tree bark, with the hawk-like guides pointing out its position as we city-dwellers struggle to focus our unaccustomed eyes.

The rain continues in spells of start and stop: soft, downpours, then full-on deluge, with thunder, before stopping once again. The sun arrives, belting out rays, leaving the forest steaming in its wake. It’s not long before the howler and spider monkeys make an appearance — hollering, shouting, even seeming to sing as they swing through the forest, a highlight for many of the group. On our return to Laguna Lodge, where we’re staying, we’re rewarded with a rare sighting of an adult and baby sloth, hanging from the branches. The adult almost waves, an arm stuck mid-motion.

Their low metabolic rate means it can take days for them to digest their food and make any sort of movement. They’re also often difficult to spot and so slow, algae can grow on their furry coat, further hiding them in the trees. This is our second rare sighting. The lodge is positioned between three strips of land interspersed by two canals, a lagoon, and on to the east, the Caribbean Sea. Earlier at breakfast, we’d been rewarded with a viewing of a dolphin, unusual in a lagoon; the waterway here is bracken, a mixture of fresh and seawater. The afternoon is ours to hang out by the pool or to find out more about the wildlife with our guides. Today, there’s the chance to learn all about frogs: specifically, the little red-eyed, green (leaf) frog, the poster-animal for Costa Rica. This trip is about making the most of the destination whatever the weather.

Later, I head to the Sea Turtle Conservancy Foundation to hear a talk on the incredible turtles that nest in Tortuguero, while the children choose to stay by the pool. As the clouds swell and deliver more rain, they’re happy getting wet in a game of their own making. Still, they join us for the ‘practical’ part of the turtle experience, an evening walk to the beach to see green turtles laying their eggs. The guide leads us to the beach, red light in hand (no torches or phones). The turtle has already nested and is in the process of laying her eggs. This 100kg hulk of a turtle, ‘Flo’, as she’s nicknamed by my daughter, needs space, as we crowd round to watch. Suddenly there are cries and pounding of feet, impromptu movement, and lots of extra space is given.

Someone has trodden on a nest of red ants, a too-late reminder to wear closed-toed shoes. The children are rightly jumpy and nervous — red ants bite! Flo is indifferent, though, doing her thing, laying egg after egg, then using her large paddles to cover the eggs with sand. She soon heads back crossing the sandy beach to the roaring sea, with riptides even the locals don’t dare challenge at this time of year.