TL;DR: I'm most productive on Friday afternoon.
I'll define "productive" as "uninterrupted time focused on individual contributor work like coding, designing, writing, etc." More on that below*.
Note: I work on a distributed team. I'm in EST, but work with folks in Western Europe and Western Americas.
Time of day:
Because I work in the middle time zone of a distributed team, and there's more people ahead of me than behind me, generally afternoons are my most productive.
Day of the week:
So Friday is the most productive day because Europe finishes before me and project works slows a bit since we don't want to ship anything major because the next day is Saturday.
So Friday afternoon is my most productive time of the week overall. I typically don't have any recurring calendar events and chat/email is mostly silent.
* I don't consider meetings or chat to be unproductive by default. Though however well-structured, a 5min chat conversation here and a 30min meeting there add up over time. Death by a thousand papercuts.
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