Meteorological vs Astronomical Seasons
Typically we define seasons here in the west according to the weather, or meteroologically. There are 3 months each of spring, summer, fall, and winter. These seasons are based on annual temperature cycles. Summer is considered in the northern hemisphere to be June, July, and August. Fall is September, October, and November. Winter is December, January, and February. Spring is March, April, and May.
Astronomically the seasons are based on the tilting of the Earth on its axis, and its orbit around the sun. There are two solstices and two equinoxes. This is a similar calendar but based on the position of the Earth and Sun regardless of the perceived temperature and atmospheric conditions.
Traditional Chinese Seasonal Nodes
Ancient Chinese seasons were divided into many small sections, largely due to agrarian culture and consideration of the qi of the environment and how it could affect one's health. These mini seasons are about 15 days each and correspond to the sun traveling 15 degrees of ecliptic longitude. There are 24 seasonal nodes per year.
That Fall Feeling
The 24 node system indicates the start of Autumn on August 7th this year, and this week we embrace a node called Chu Shu, or "heat hides." This node marks the lessening of summer heat. During this phase of the year, although heat may be still very much present, it can start to be inconsistent. It may also be noticeable that the angle of the sun is changing and the shadows are getting a little longer.
Sometimes when it feel like one season, but we are prepping for another, like back to school, and pumpkin spice lattes in August, we are actually right in sync with these smaller seasonal division.
Affects on Health
Nodes can be helpful to think about as we make seasonal transitions. It's time to prepare our wardrobes so that we're not caught off guard during sudden changes in weather. It is also important to gently expose our bodies to the cooling temperatures so that we acclimate to them, while simultaneously avoid sweating outdoors. This is a sensitive time of year for the Lungs which govern the skin and in part the immune system.
It is also seasonally appropriate to adjust activity level to reflect the decreasing yang and increasing yin of the environment. We can do this by practicing more gentle exercise routines and getting more sleep.
Additional Resources
List of solar seasonal nodes here
Tips to adjust to the fall season here
Tips for eating with the Autumn season here
cover photo credit