The Online TurboTax website is available 24/7 for account access, for preparation of an Online return, purchasing software (CD/download), etc.
This user community forum is available 24/7, but at night it's mostly fellow users and volunteer helpers. In the daytime, more TurboTax Support agents are also in the forum.
Customer Support phone hours during filing season are 5AM-9PM Pacific (8AM-12 Midnight Eastern) 7 days/week. Free Edition does not include phone support, unless one has the PLUS option with it.
FAQ: How do I contact TurboTax?
https://ttlc.intuit.com/replies/6386875
