I started a thread a long time ago regarding this. The grammar part.
The weather person from that City news should know that proper English is " windchills between -30 AND -40" or just "windchill of -30 to -40". And I would pick the former either way. It is the word between that turns the grammar wrong. I had someone with knowledge in this confirm in the thread that it is wrong. Yet so many people in Canada don't even realize.
People think that because the word to is used in some contexts like the latter, that it is correct in others like this. But they are wrong.