Jack Dykinga / Lightning storm with rainbow over Saguaro cactus (Carnegiea gigantea) near Redrock, Arizona State Trust, Sonoran Desert, Arizona. September 2015. Long exposure with lightning trigger.

Luciano Candisani / Clouds reflected in flooded field at the end of the wet season, Pantanal, Brazil

Niall Benvie,Niall Benvie / Alto cumulus clouds. Angus, Scotland, August 2012.

Jack Dykinga / Cheyenne River Sioux Tribal Park with severe storm clouds at sunset amid vast grassland, South Dakota, USA

Philippe Clement / Cumulus mediocris clouds, Luxembourg

Tim Fitzharris / Grassland and cumulus clouds, Wind Cave National Park, South Dakota

Shattil & Rozinski / Cumulus clouds over the Red Desert, Wyoming, USA

Yva Momatiuk & John Eastcott / Grand Teton peak with cumulus clouds, Grand Teton National Park, Wyoming

Yva Momatiuk & John Eastcott / Heavy cumulus clouds gather before storm above sagebrush desert, central Wyoming

Shattil & Rozinski / Thunderstorm, heavy rain and rainbow under cumulus clouds, USA

Yva Momatiuk & John Eastcott / Adelie Penguin (Pygoscelis adeliae) flapping wings, Holtedahl Bay, Antarctica

Philippe Clement / Cumulus congestus clouds over land, Belgium