https://translate.google.com/#view=home&op=translate&sl=auto&tl=ru&text=the%20weather%20is%20ussally%20fine

FINE and PLENTY are the same as GOOD and ENOUGH, except that they have a nuance of assurance. You use them when there's a suggestion that something isn't good/enough, or a fear that something isn't good/enough.

[daughter]: Mom, does this dress look ok for me to wear to a wedding? I think it's a bit informal, no? [mother]: It's fine! Just wear some nice earrings and a necklace with it. = don't worry - it's good for a wedding

[mother]: Charlie, I put an extra sandwich in your lunchbox since you're going to soccer practice after school. Do you need another drink in there, or is one soda enough? [son] That's plenty - they always have bottled water at soccer practice. = don't worry - that's enough

So, we would say "the weather's fine" if someone had trepidations about moving somewhere because of the weather, or planning an outing in case of rain: A: I've been offered in a job in your city. But isn't Seattle famous for bad weather? B: The weather is usually fine - we only really get rain in the summer. = don't worry - the weather is good for the most part.