Why is the definite article used before mid-40s and 30s in this sentence from a Washington Post weather report?
Highs are mainly limited to the mid-40s, with wind chills in the 30s so bundle up.
I am confused because I don't see what is being specified and thus calls for the article, and also because the same site has other lines without the definite article. The following sentences contain a mix of usages with and without the article.
The incoming surge of colder air pushes lows into the mid- to upper 20s, with low 30s limited to downtown.
Winds finally begin to die down overnight under starry skies. Lows range from mid-20s to low 30s.
Highs get up to the more seasonable mid-50s. Overnight is clear, with lows in the upper 20s to mid-30s.