I am the client not the server. Maybe you are asking whether I check the CN or compare the certificates every time I connect against ones I have stored locally. I could, but for these two sites I don't. Am I worried about someone spying on the local rain radar images or wind speed data I am retrieving. No. There's nothing confidential about this information. Nor am I worried about being secretly routed to an "evil weather service impersonator" without me detecting the change. One of the adresses belongs to a government agency. These addresses do not change often, if ever.
Doesn't Lets Encrypt allow IP adddresses for the CN.
