Problem is ...
It's not in the sort of shade used for standard measurement: in a vented, white-painted box, 2m above a grass surface, in the middle of a clear space, at twice the distance from nearby objects as those objects are high.
What it means is that the 'pond' temperature is indeed what you enjoy/suffer as you sit there, but isn't what counts towards the report on the evening news. In fact, we often experience temperatures significantly higher/lower than the 'officially' recorded ones.