I read an article on climate change which used the expression 'extreme high temperature'
Extreme high temperatures set to break records: ANU expert
I understand that 'extreme' can mean extremely low or extremely high. But since the article is using the word 'high', isn't the usage 'extreme high' redundant? So I figured that it must have been a typo, and that the author probably meant 'extremely high'. But just to be sure, I did a Google search and was surprised to find that this usage is quite common.
MWD defines 'extreme' as:
a : existing in a very high degree extreme poverty b : going to great or exaggerated lengths : radical went on an extreme diet c : exceeding the ordinary, usual, or expected extreme weather conditions
2 archaic : last
3 : situated at the farthest possible point from a center the country's extreme north
4a : most advanced or thoroughgoing the extreme political leftb : maximum
5a : of, relating to, or being an outdoor activity or a form of a sport (such as skiing) that involves an unusually high degree of physical risk extreme mountain biking down steep slopesb : involved in an extreme sport an extreme snowboarder
Now, the 'extremely low' aspect is not given anywhere in this definition, but TFD does define it as
Either of the two things situated at opposite ends of a range: the extremes of boiling and freezing.
What I want to know is whether the usage 'extreme high' is correct, and if it is, how is it different from 'extremely high'.