Q: When do the seasons begin according to the inner dimension of the Torah?
A: The year is divided into 4 periods – fall, winter, spring and summer. Each period begins on the first of the month of the corresponding season. Fall begins on the first of Tishrei, winter on the first of Tevet, spring on the first of Nissan, and summer on the first of Tamuz. In the Temple in Jerusalem, the first of every month, (Rosh Chodesh) was a "mini holiday." Today Rosh Chodesh is marked by special prayers and many Jews also have a festive meal to mark the day.
Every turning point of a season is actually a point of nullification of the previous season. A person can reflect this nullification within himself in order to inspire a (positive) turning point in his own life.