In my native language, we have the word "mezzutemp" (literally translated to middle-weather) to refer to the weather between summer and winter, where it constantly changes from summer weather to winter weather (or vice versa). For instance, we may have a sunny day today, an extremly rainy day tomorrow and another sunny day the next day. The "mezzutemp" is said to end once the weather settles down and is more constant and in line with its season. If there is a sudden jump from summer weather to winter weather (if it goes from extreme heat to constant rain and cold), we would say that we did not have any "mezzutemp" that year.
Is there a single word in English to refer to this concept of in-between unpredictable weather? I can only think of the phrases "spring weather" or "autumn weather", and while they are close to "mezzutemp", they are not an exact translation.
