Did the framers specify a particular day or frequency for Congress to meet in 1787?

1. What the framers wrote — a clear calendar instruction

The Constitution, drafted in Philadelphia in 1787, explicitly set both a minimum frequency and a default day: Congress must meet at least once each year, and that meeting “shall be on the first Monday in December, unless they shall by law appoint a different day” (text summarized in modern congressional histories) ^{[1] [2]}. Senate historical pages emphasize this language as an intentional scheduling rule emerging from the Constitutional Convention ^{[2] [4]}.

2. Why December? The framers’ practical motive

Contemporaneous explanation recorded in Senate histories credits the framers’ agricultural frame of mind: December was largely “dormant” after harvest, making it convenient for legislators to travel and tend to business without conflicting with planting or harvesting seasons. That agricultural logic undergirded the choice of the first Monday in December as the constitutional default ^{[2] [4]}.

3. Practice vs. text: The First Congress and an earlier start

Despite the constitutional default, the First Congress actually met March 4, 1789 — a convening date established by a resolution of the Congress of the Confederation — and did not attain a full quorum until April ^{[3] [5]}. Later Congresses often diverged from the December default by statute or custom; the historical record shows multiple early acts permitting different meeting days ^[1].

4. Flexibility built in — “unless they shall by law appoint”

The framers deliberately added a safety valve: the Constitution’s December rule applied only “unless they shall by law appoint a different day,” which allowed Congress (or subsequent statutes) to set alternate convening times. Through the 18th and 19th centuries Congress regularly used that authority: by 1820 there had already been many acts changing meeting days, and practice continued to evolve ^[1].

5. Long-term evolution: March dates and the 20th Amendment

Under the original constitutional calendar and subsequent practice, the formal start of a Congress and its sessions frequently fell on March 4 (or March 3 in some reckonings), a schedule that persisted until the Twentieth Amendment. Ratified in 1933, the Twentieth Amendment moved the formal meeting and term-start to January 3, replacing the earlier defaults rooted in the 1787 Constitution ^{[6] [2] [7]}.

6. How historians and institutional sources present the story

The U.S. Senate’s history pages and the House’s institutional histories both present the same core facts: the Constitution set the first Monday in December as the default annual meeting day and required at least one meeting a year, but early practice and later amendments changed actual convening dates ^{[2] [1] [3]}. Public-facing timelines and Capitol educational resources reiterate that the Constitutional Convention of 1787 created the legislative framework that was then adapted in practice ^{[8] [9]}.

7. Points of disagreement or nuance to watch for

Sources agree on the constitutional text and the December rationale, but they also show a tension between constitutional design and early practice: the First Congress began in March 1789 by Confederation resolution despite the December default, and numerous early statutes altered meeting times as needed ^{[3] [1]}. If you encounter claims that Congress always met in December from 1789 onward, that overstates the case; available reporting documents early exceptions and statutory adjustments ^{[3] [1]}.

8. Bottom line for your question

Yes — the framers did specify both a minimum frequency (at least once a year) and a particular default day (the first Monday in December), but they also permitted Congress itself to change the date by law; in practice early Congresses met on other days (notably March 4, 1789 for the First Congress) and the schedule was later changed permanently by the Twentieth Amendment ^{[1] [3] [2]}.