In the Arabian Gulf, there's a lot of muddy, mucky water covered with mangroves, and fauna such as flamingos and dugong/manatee populations. At night and in the mornings, there's a thick fog over these areas, even though this is one of the hottest regions of the world.
I like the other answers, just adding another existing situation. This is us mucking through the swamp in the middle of summer with kayaks and sunblock in Abu Dhabi. Heaps of swampland all year round, with little islets and a diverse ecology. There also exists a lot of marine diversity as well.
The requirement for this kind of ecology is slow flushing - the movement of water should be slight tidal up/down in an area with clean water and limited flushing in a climate that has hot days and cold nights (coastal desert). Sediments are a mix of sand and organic soils between freshwater and salt water (estuary), and is immediately against a desert landscape.
EDIT: As requested, more pictures.