This is translated “How strange the weather is!” but this seems to be understated or milder than the German sentence. “verrücktes” is usually translated “crazy” which would be fine, and I think “crazy weather” would be my preferred translation here, and in this context I could also see translating it “bizarre” or “weird” or perhaps even “wild”. I.e. some word that would carry greater intensity. In English, saying “strange” weather connotes something like, unseasonably warm or perhaps the lighting looks weird, but not as aggressively weird. Whereas “verrücktes” seems to connote something a bit more aggressive, like sharply changing temperature, heavy and inconvenient rain that comes seemingly out of nowhere, or something of the sort.