Why, except in summer. Winter, autumn, spring, rainy days are always more than sunny days.

Because spring is the season when everything grows, and it needs the nutrients of rain. In autumn, the weather becomes cold and dry, and rain drops are needed. Winter is the coldest season in the whole year, so it rains and snows. Needless to say, summer is hot because the sun is too big and the ultraviolet rays are high.