The light, relief and climate of his native Cantabria are ever present in Juan Uslé's paintings. His paintings are like large pages of colourful writing, evoking abstract landscapes. In small, jerky strokes, he creates bands of shimmering, vibrant colours that can evoke reflections on water, shades in the sky or the effect of the wind rippling on green hills.

The "Viento Sur" (the south wind) is a well-known wind in Santander. Its warm air rushes down the mountain, sometimes in very violent gusts, right into the bay. Its influence on men and women is mythical. Nicknamed "viento loco" (the crazy wind), it is said to cause mood swings, headaches, respiratory illnesses, nervous breakdowns etc. In his work, Juan Uslé focuses on the change in perception he brings to bear on distances, volumes, light and landscape. When the south wind blows, the artist likes to climb up into the mountains to observe and listen to the sea. He has always been sensitive to this phenomenon, whose influence can be seen in his painting. In 1993, he told Barry Schwabsky: "You're in the north where the wind is normally cold, but when it gets hot your vision of space goes crazy. That's why I don't want to freeze everything. I would like viewers to work a little too, to play with the elements of the painting and make their own films" (interview published in "Tema Celeste" in 1993, reprinted in "La peinture dans son temps", a collection of interviews with the artist published by Galerie Lelong & Co. in 2021).