Seetha performed Sandhya rites

Sri Hanuma enters the Ashoka garden and observes its beauty. He starts looking for Seetha in the garden.  Sri Hanuma saw a mountain,  which was surrounded in all directions by peaks, spread by caves and covered by different trees and a river, which fell down from the mountain.

Sri Hanuma saw near to that mountain, lotus ponds together with many groups of birds.  He also saw an artificial pond filled with cold water, with steps embedded with best diamonds, shone by the sand of pearls, wonderful forest with very big buildings made by Vishwakarma, with groups of artificial trees decorated in all directions.

Sri Hanuma saw one Shimshupaa tree golden in colour covered with many groups of creepers and with many leaves surrounded everywhere with platforms made of gold and climbed up that Shimshupaa tree

He thought that Seetha would definitely come to that garden if she were to be alive.  He also thought that Seetha , interested in the rites of Sandhya time,  will definitely come to that river, with the auspicious water, for Sandhya rite.

संध्या काल मनाः श्यामा ध्रुवम् एष्यति जानकी |
नदीम् च इमाम् शिव जलाम् संध्या अर्थे वर वर्णिनी ||  

(Sundara Kanda 14th Sarga 49th Sloka)

"The ever youthful one with the best complexion, Seetha interested in the rites of Sandhya time will definitely come to this river with the auspicious water for Sandhya rite."

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It appears to me that at the time Srimad Ramayana, women used to perform Sandhyaa rite along with men.