I suppose that would be extreme - or in the argot of the field - "anomalous"
outstanding, exceptional, superlative
The opposite of not high is high.The opposite of high is low.
Low is the opposite of high.
the opposite world of high is low.
How about low?
It is low.
average high/low temperatures
The opposite of lowest is highest. Just like how the opposite of low is high.
The homophone for the opposite of "low" is "high." This pair of words sound the same when spoken aloud but have opposite meanings.
In january the average high is 27 and the average low is 10. In july the average high is 81 and the average low is 60.
it is high tide
it is high tide
The opposite would be high, with specific terms being raised, increased, or elevated.