Thank you for your answer!

In the example you gave, this is more of an invitation to engage in “small talk.” So the answer would be your opinion on the weather. Ex: oh, yes it’s gorgeous! Or: oh, you think so? I prefer cooler weather. You certainly don’t have to answer, but if it’s someone you know, it could seem a bit cold or standoffish depending on the context. Tag questions can also have a rising intonation (right?!) And simple information questions often have falling intonation (ex: what time did the party start?) and a lot of them could have slightly different meanings or give a different tone with the same words but a rising / falling intonation (ex: the last question said with a rising intonation implies surprise or possibly disapproval whereas a falling intonation just requests information. You can also stress different words in the same question to imply different things as well.)