Why every day of the year (almost? The weather is the same.

This is the periodic law of the "climate" in this area. This question can't be answered clearly in a few words, but I can give you some exploratory suggestions:

1. In your question, you mentioned two concepts of time: year (share) and day (date). These two concepts are the objects of "astronomical calendar" and the periodic laws of geographical and astronomical scales.

Climate is a smaller scale within its scope. China's ancient understanding of climate is a concept of time, and modern science regards it as the concept of atmospheric rhythm: Qi is a concept of time in groups of ten days, and climate is a concept of time in groups of five days. The "climate" combining the two refers to "average weather conditions".

There is another concept in your question: weather. It is a short-term atmospheric phenomenon in a place, which changes all the time and has differences all the time.

3. You find it difficult to ask your own questions: you use the word "almost" in () to express your uncertainty about time and phenomena, which is actually a kind of "meteorological feeling based on fuzzy time" in the eyes of Chi Ge.

So you can find the answer to your question in Four Seasons of the Year, Twenty-four Solar Terms, Earth Movement and China Monsoon Climate.