Ramayana Masam is observed to bring out the importance of Ramayana and not of the month.Karkidakam month is often called "panja masam" (lean season).New ventures and auspicious functions(Wedding,House Warming,Vidhyarambham etc ) are not held during this month.Karkidakam marks the begining of Dakshinayanam(southern movement of the sun). Inclement weather,poverty and diseases are the highlights of this month.The effect of which is reflected in mankind and in all living beings. As per Ayurveda shastra this time is good for all health treatments such as Pizhichil ,Uzhichil etc..The change in the sun's path has significant impact on human beings also.
Human body and nature are closely associated.Both bodies are made up of Panchabootham(Earth,Water,Fire,Air and Sky). Any change in Prapancha Sareeram(Nature) has a direct effect on Human body and the society.This is based on the Prana (Life Force) and the body.Phenomenon of Uttarayana and Dakshinayana based on the celestial equator path is also present in the Human body.As per "Jabala Darsanopanishad" Sushumna Nadi is the celestial equator path,Ida Nadi is Dakshinayana path,Pingala Nadi being Uttarayana path.Sun's position in the equator corresponds to Prana(Life force) in Sushumna Nadi.Ida Nadi is called Chandra(Moon) Nadi and Pingala Nadi as Soorya(Sun) Nadi.This is how the human body and the Prapancha Sareeram(Nature) are related.
Following sloka describes the Uttarayana and Dakshinayana in human body.
Pingalayam Iddayam tu
Vayoch Samkramanom tu Yat
Iddayam Pingalayam tu
Pingalaya Mithi Srutih
Movement of Prana Sooryan from Pingala to Ida is called Uttarayanam. Movement of Prana Sooryan from Ida to Pingala is called Dakshinayanam.The movement of Prana Sooryan is similar to that which occurs in the Prapancha Sareeram(Nature).When Prana Sooryan traverses through Ida its called Apanan(Dakshinayana Sooryan) and through Pingala it's called Pranan(Uttarayana Sooryan).Apanan starts at the same time when Karkidakam month starts and is responsible for material or negative thought waves.Pranan is pure and is responsible for spiritual or positive thought waves.
During Dakshinayanam period human body is more prone to material or negative thought waves.To overcome the bad effect of Apanan, Ramayan is recited so that spiritual or positive thought waves overide material or negative thought waves.For a person who does daily recital of Ramayan Karkidakam month has no significance since all round the year spiritual or positive thought waves are created.
Ramayana Masam concept taken from "രാമായണമാസാചരണം കര്ക്കടകമാസത്തിലായത് എന്തുകൊണ്ട്?" written by Jagadguru Swami Sathyananda Saraswathi Tiruvadikal.