Generally speaking, it is easy to know or predict the date of every state’s presidential primary in 2020, except for New York.  The statute says the New York 2020 presidential primary will be on February 4, but that is very unlikely to stand.  Both major parties refuse to recognize primaries earlier than March 3, except for the New Hampshire and South Carolina primaries.  Everyone expects the New York legislature to pass a bill this year setting a March date, but so far no bill is pending.