Matt Cutts is likely to sleep between 1 a.m. and 7 a.m.
Matt Cutts - I'm the head of the webspam team at Google.
Matt Cutts is located in Bay Area, California (Pacific Time (US & Canada) time zone). If the sleeping schedule doesn't appear right, maybe @mattcutts hasn't specified the correct timezone in their Twitter profile.
Use the search box to know the sleeping schedule of another Twitter user.