cher·ry-pick
/ˈCHerēˌpik/
verb
choose and take only (the most beneficial or profitable items, opportunities, etc.) from what is available.
"the company should buy the whole airline and not just cherry-pick its best assets"
the author did not cherry pick. in order to cherry pick, the author needs to have had a predetermined thesis such that cherry picking only certain data points would bolster said thesis. instead, the author was looking to see what the deal was with long-term observed weather in specific places relevant to the author, then later expanded to include a few other locations as well. therefore, unless you are accusing the author of being dishonest, the author did not cherry pick.
How do you know he didn't cherry pick these weather stations? One thing to say that it's not clear whether he did, another to claim - as you have in your post - that he did not.