It is a hot summer’s day; there’s not a cloud in the sky. You, and your friends or family, make the decision to go to the beach.
As you run through the house, gathering flip-flops and towels and swimsuits, you imagine warm sand, blue-green water, a slight breeze.
You put on your sunglasses, get into a boiling hot car, and roll down the windows. Then you drive through sunny countryside, the wind in your hair. When you near the coast and smell the scent of the sea, your heart jumps with excitement.
Now the air is cooler, the sky less bright. But those clouds will quickly blow over! You roll up the windows. The weather is dull, but perhaps … the sunny spot is a mile along the coast.
The clouds are darker. You put on a jacket before stepping out of the car. Thank goodness you had the foresight to bring one! You walk along a path through the sand dunes, and look at the sea. “I’m freezing,” says one of your friends.
“Me, too,” says another. “I saw a café, two or three miles back. It looked like it might have views of the harbour.”
You’re a hundred yards from the car when a hailstorm starts. Your hair is wet and your legs are covered in goose bumps.
The café that might have views of the harbour looks empty and sad. You keep driving.
Ten miles from home you take off your jacket, then roll down the windows. The warm wind dries your hair. You, and your friends or family, spend the late afternoon sunbathing in your garden.
Why does this happen?
It is the fault of brown seaweed, otherwise known as kelp. Scientists believe stress among the plants can alter weather patterns.
On an overcast day kelp are comfortable when the tide goes out, as they stay damp until it comes in again. But on a bright day they dry, releasing iodide. The iodide rises, causing clouds to form overhead, sheltering the kelp from the unwelcome sunshine.
Never, ever, expect a sunny day at a beach where kelp is found in quantity.