The season integration will provide the current astronomical or meteorological season (Spring, Summer, Autumn, Winter) as a sensor.
Adding Season to your Home Assistant instance can be done via the user interface, by using this My button:
If the above My button doesn’t work, you can also perform the following steps manually:
Browse to your Home Assistant instance.
In the sidebar, select Settings.
From the configuration menu, select Devices & Services.
In the bottom right, select the Add Integration button.
From the list, search and select Season.
Follow the instructions on screen to complete the setup.
For information on the difference between astronomical and meteorological seasons please see the link below:
All information about how the seasons work was taken from Wikipedia:
To cut a long read short, Astronomical gives seasons based on the shortest/longest day and equinoxes. So in the Northern Hemisphere spring starts on 20 March). Meteorological gives seasons based on months (so in the Northern Hemisphere spring starts on 1 March).