Head bath with oil must not be taken before sunrise on all days except on Deepavali day.
Working women can take a head bath with oil on any holiday after sunrise. But on certain unavoidable times or during festival days women can meditate upon Emperuman and can recite Perumal Thirumozhi pasuram 2-2 provided here –
Women can chant the divine name ‘Pundarikakshan’ and contemplate on Emperuman who resides in the sun while taking a head bath before sunrise though this is a secondary option only.