The term "cat and dog weather" is a well-known expression used to describe heavy rain accompanied by thunder and lightning. However, when it comes to antonyms for this term, we can think of several opposing ideas. First of all, we could use the antonyms for "cat" and "dog" themselves. For "cat," we might use "dog" or "canine," while for "dog," we might employ "cat" or "feline." An antonym for "weather" could be calm or clear. Hence, we might say "clear, calm day" as an antonym for the phrase "cat and dog weather." However, in general, it is worth noting that there are not many direct antonyms for a phrase like "cat and dog weather.