What a difference a degree or two makes

The Dart is well known for being a flashy river - up and down like a tart's drawers as someone remarked.  When we arrived for our regular Sunday dip there was a tide mark of twigs on the grass, showing that the river must have been really high in the last day or so.   When we got in it felt distinctly warmer than our last swim a week before.  For a start, I didn't have the feeling of millions of tiny daggers pricking my legs as I took the plunge, which I've had the last couple of times we've swam.  It turned out to be nearly three  degrees warmer - 7.7 - which made a big difference.