Karadayan Nonbu, Karadaiyan Nombu, Karadayan Vratam or Savitri Vratham, is a vow observed in Tamil Nadu on the last day in Maasi masam or the Masi month in Tamil calendar. This festival also marks the Meena Sankramanam or the transition of Sun into Meena Rasi (Pisces) from Kumbha rasi (Aquarius). In 2013, Karadayan Nonbu date is March 14.
Married women worship Goddess Gauri or Parvathi or Shakti for marital bliss and better health of husband and children. Unmarried girls perform the vratam to get ideal person as their husband.
The time to observe the Savitri vratam may differ from region to region in Tamil Nadu.
Karadayan Nonbu is similar to that of Soubhagya Gauri Vratam or Gauri Tritiya vratam of Andhra Pradesh and Karnataka, Gangaur vrat of Rajasthan, Jyeshta Gauri Vrat of Maharashtra, Jitiya Puja of Bihar, Karva Chauth of all other North Indian states festivals. This vratham is very much similar to Vat Savitri vrat observed in Bengal, Orissa and some other places of India.