Agree with last post - is your fridge vented into an awning by any chance - will make it worse again.Hi Tina,
The condensor fridge has a maximum temperature diffrence, cant remember what it is, but basicaly, if it's very hot outside, your fridge wont get as cold as normal.
you can increase it's perfomace (speed of cooling) by adding a fan as Bill says. But there's not much you can do to get it any colder.
They do normaly work brilliant but last week was a scorcher.