Author's Note: This is a three part article giving insight into the traditional six Vedic seasons.
In the first article about the zodiac, I compared seasonal and stellar correspondences.
In the second article aims to give a felt-connection to the emotional nature of the seasons.
Rtu Chakra Wheel of the Seasons by Freedom Cole
Months (Sāyana māsa)
Madhu and Mādhava
Śukra and Śuchi
Nabhas and Nabhasya
Iṣa and Ūrja
Sahas and Sahasya
Tapas and Tapasya
The seasons made Prajapati (the creator) sacrifice with them, and because of that he prospered.  This is the ancient reasoning behind Vaidik seasonal rituals: because the seasons
made the creator god do it, and it made him successful. But the deeper implication is that the seasons are the Natural Order, and even the creator must
follow this order – even he must be in tune with the seasons. Prajapati (as the Creator) is the year itself, consisting of twelve months. 
praises the seasons, each composed of two months. The Spring is composed ofMadhu and Mādhava. Madhu means sweet or pleasant, and is often used in Sanskrit literature as a synonym for the springtime.Mādhava means sweet and intoxicating, and relates to the joy of Spring. Śukra and Śuchi relate to the brightness and light of the Summer. Nabhas and Nabhasya relate to the clouds and skies of
the rainy months. Iṣa and Ūrja relate to the food and nourishment of the harvest time. Sahas and Sahasya relate to the
strength of the enduring through the cold. Tapas and Tapasya relate to the austerity of the earth at this time.
In the Ṛgveda we see the year divided into twelve parts, but in the Taittirīya Saṁhitā (a Yajurveda text) we see those twelve
months named. Past scholars have pointed to the Babylonians as first dividing the
year into twelve months, but these texts are comparable to, if not earlier than, the Babylonian references we have. These divisions in the Taittirīya Saṁhitā clearly have both seasonal and astronomical implications.
(VI.5.3) speaks of the gods attaining heaven by sacrifice; and realizing that man
would follow, they blocked the way to Heaven by the year. The sages (Ṛṣi)
discerned through the season vessels (ṛtu-pātra) the way to reveal the world of the heavenly stars (svarga loka). The revealed knowledge is the division of the year into twelve months grouped into six seasons.  Through the seasons, the worshipper makes a bridge to heaven. This section of
the Taittirīya Saṁhitā goes on in mythical Vaidik language to discuss Indra, Agni, Venus (Śukra), Jupiter (Bṛhaspati) and the
birth of the Ādityas, all deities relevant to astrology.
When the seasons are confused, season-vessels (ṛtu-pātra) are drawn for the Maruts (wind/storm gods) who reveal the seasons.  Marut-patha is known as a region of air or space, and the vessel of the
Maruts (Marut-pātra) is similarly a region of space created in the sky that allows the timing of the seasons to be clarified.  The Saṁhitā mentions different ways of calculating, which goes back to
the sidereal and tropical discussion. It may be referring to sidereal calculations that were regularly updated by adjusting new sidereal information to
In Jyotiṣa texts we see the use of astrology to predict about the seasons. It is common to predict the year’s rainfall from astrological indications. In
Āyurveda, Charaka discusses how abnormalities in the stars (nakṣatra), Sun, Moon and planets indicate that the coming season will have some
abnormalities. In Charaka Saṁhitā, Sage Punarvasu mentions the
astrological indications necessary to prepare the herbal medicine that will be needed for community epidemics.
Changing Seasons (Ṛtu-Sandhi)
Seasons last for approximately 60 days, composed of two 30-day months. The transition between seasons is called ṛtu-sandhi.  Bharata’s Nāṭya Śāstra compares the transition between seasons to the
common ground between two notes in an octave called svara-sādhāraṇa, an in-between note having the properties of both. 
The Rainy Season–Autumn transition is described as the kadamba trees still raining their flowers. The ṛtu-sandhi most discussed is the Winter–Spring ( śiśira-vasanta). When the Cool Season is ending but Spring has not yet set in, the poets describe it as still cold in the shade, and yet one
sweats when the midday Sun comes out. It has also been described as Lady Spring holding a sprouting mango branch, wanting to step into the flowering
forests with the sound of the bees on the lotuses in the ponds.
The first week of the season is called sandhi. The next period is its infancy (śaiśava) where the attributes of the season begin; and
then the mature phase (prauḍhi) gives the full nature of a season. The last phase of the season is the continual transition (anuvṛtti)
where the next season is beginning and the present season is ending. Officially, the ṛtu-sandhi is the last week of the previous season and first
week of the next season, but the actual sandhi experienced will change depending on the location. The farther north, the longer the cold season
lasts; and in the northern regions the cold comes sooner. The rains will also start in different parts of India at different times as well.
The ṛtu-sandhi are known to cause disease. The human body has adapted to a particular environment, and then situations change. This is why colds
and flus are most common at the beginning of the Winter time. It is the transition to the cold, not particularly the cold itself, that creates sickness.
The majority of epidemics will break out during these ṛtu-sandhi as well, since people’s immune systems are weaker at this time.  In Āyurveda, seasonal routines are very important in order to stay in balance
during a season and its transition. During the two weeks of ṛtu-sandhi, one begins to change one’s diet slowly. If the change happens too quickly
that can also disturb the body’s balance (asātmya).
In Āyurveda the goal is to protect health, and only when one has failed at this is disease being treated. The various rules and regimes (carya)
employed to stay in balance as the seasonal environment changes are called ṛtucharya. Most Āyurvedic texts mention these practices in the first
few chapters to highlight their fundamental importance. Charaka says that one who
follows the seasonal routines will have strength (bala) and good lustre (varṇa). 
The environment is in continual motion (nityaga), which means there is a need for continual adaptation to change. The goal of Āyurvedic seasonal
routines is to help the body keep its equilibrium through the regular seasonal variations. The Āyurvedic texts list details about foods, clothing, daily
routines, massage, conduct, frequency of sex, sunlight, etc. The issue arises that the climate varies all over the world – the seasonal routine
followed in Southeast Asia cannot be followed in Europe, Africa, or the Americas. In the Indian Summer, vāta accumulates because the heat is dehydrating;
but on the east coast of the USA, the summer months are hot and extremely humid. The rainy season in India is hot Summer rain, compared to the Winter rain
of California. These differences show up in the type of plants and vegetation that grow in a particular location.
When we understand the basic concept of how to keep equilibrium, it does not matter where we are, as we will be able to adjust accordingly. Balancing is
about eating easy-to-digest, hot foods when it is cold outside; and when it is hot, eating and drinking cooling foods. When it is dry, one should make sure
to moisten and oil the body’s tissues, and when it is moist be sure to avoid congestive foods. Āyurvedic seasonal routines (ṛtucaryā) seek to give
knowledge of how to adjust to the seasons. This requires both an awareness of the environment and awareness of one’s own body. The path to having this
awareness brings wholeness in the body, mind and spirit. When we are ‘connected’ and aware, then we are walking towards wholeness.
A wise person does not wait till they are sick to seek the knowledge of connected balanced living. It is important to make it part of a healthy life and
keep sickness away. Since seasonal routine is very individual to the location where one lives, I recommend taking classes or seeing your local
Āyurvedic practitioner regularly until you have a grounded concept of how the environment affects your body’s biology, and what can be done to stay in
balance. A local practitioner will have a concept of the local climate to be able to share the ‘what’ and ‘when’ of your local seasonal routines.
The Seasons as Teachers
The seasons can be calculated astronomically, or they can be felt by observation and awareness. Being aware of the temperature and humidity and how it
affects our body is connecting and aligning with our physical environment. By being aware of the emotional shifts that we experience as the seasons change,
and consciously working with them, we are aligning our mind and emotions to the planetary mind. By being aware of the movement of the Sun and the length of
the days, and adjusting our schedules accordingly, we are aligning with the greater solar system surrounding us.
Living in a modern box with electricity and technology disconnects us from nature and the seasons. This disconnection gives the false sense that we are
autonomous from the environment that we live in. But we eat the environment, and are made of the environment, and are impacted by its changes. We are made
of these seasons, and they guide our feelings, emotions, and activities.
I hope you have now connected to the seasons in a deeper way than you did before, and learned new ways to perceive them. May this awareness continue to
grow as the seasons themselves become your teacher.