Winter has hit the Algarve and whilst temperatures are still hitting 20+ during the days, the nights are cold.
Last night my sensor reached exactly 0.0 Celsius on my back terrace which meant that other areas locally dropped below freezing. There was a widespread frost that was stunning but my attention was directed at the Steam Fog Rising from the river.
{Click image(s) to view on Flickr - opens in new tab}
The Steam Fog is caused by the winter night cool air settling over the warmer water. The warm water vapor evaporating from the river is trapped by the cool air causing the water to condense which results in tiny water droplets suspended in the air.