Weather channel always changes maxima

[qwertyK]

So today for example, the maxima for my area was forecast as 4C, by the Met Office, BBC, And the weather channel. But by the end of the day, the weather channel believes it has gone as high as 7C! It usually starts this really weird change around midday. Then you see it revised down to about 2-3C lower, in the past weather. Today it felt nothing like 6 or 7C, even with a wind chill. Has anyone else had experience with this odd phenomenon, and what weather app is the beat, especially when it comes to viewing past weather?