Ayurved lays a lot of emphasis on suitable diet and regimen for every season. According to seasons the year is divided into six parts. The northward movement of sun and its effect of dehydration brings about three seasons beginning from late winter to summer. The southward movement has the effect of hydration and gives rise to three seasons beginning from monsoons to early winter.

The knowledge of diet and regimen is incomplete without the knowledge of seasons. The period of uttarayana or dehydration is called adana kaala and includes Shishira, Vasanta, and Grishma. Shishira begins in January and ends in March, Vasanta is March to May and Grishma is from May till July. The period of Dakshinayana or hydration is called visarga kaala and includes Varsha, Sharat, and Hemanta. Varsha, begins in July and lasts till September, Sharat is in September to November and Hemanta is from November till January.

In the period of Visarga winds are not very dry as they are in the period of adana. Visarga kaala predominantly shares the qualities of Moon. During this period moon with its unstrained cooling property has the delightful effect with its soothing rays. The period of adana kaala is dominated by the qualities of agni or sun. In the visarga kaala not only sun with its rays but also winds with their sharp velocity and dryness absorb the moisture from the earth, winds progressively bring about dryness in the atmosphere which enhance the bitter (Katu), astringent (Kashaya), and pungent (Tikta) rasas or tastes having drying effects on the body thereby causing weakness in the body.

During rainy season, autumn and early winter the sun moves towards south and its power of heating because of time, its course and rains and storms is slackened but the moon is not affected. The earth is relieved of heat and drugs which are sour (amla), salty (lavana), and sweet (madhur) in nature and cause unctuousness in the body grow in this season. These tastes have the effect of strengthening the body.

In the beginning of the period of visarga and the end of the period of adana, weakness prevails in the body. In the middle of both body gains moderate strength however, at the end of visarga and beginning of adana, body gains considerable amount of strength.

Diet and regimen for winter
During the cold winter, the digestive power is enhanced as a result of restraint caused by the cold wind so much so that it is capable of digesting foods which are heavy in nature irrespective of the quantity they are eaten in. When it does not get the proper fuel, the digestive fire affects the nutritive fluids and results in disturbing vata which is cold in nature. Therefore, during winter one should take a diet consisting of good amount of fats and foods which are salty and sour in nature. Even moderate amount of wine is allowed in this season. One should include honey and nuts also in the diet along with seasonal vegetables and fruits. One who habitually takes preparations of cow's milk, cane juice, fats, oils, new rice, and hot water during the winters is sure to gain strength and vitality.

In winters one should resort to massage and application of oil on the head and stay indoors. One should ensure that beddings, seats are well covered by heavy wrappers, silken cloth, blankets, etc. "Its only in winters that excessive indulgence in sexual activities is allowed provided one is taking heavy and nutritious diet" (sutrasthana VI:17). One should avoid diets and drinks which are light in nature as they aggravate vata, which is cool in nature.