December was the best of times and the worst of times — depending on which Massachusetts casino you ask.

Encore Boston Harbor had its best gaming revenue month in December since the $2.6B resort opened in June, according to new data released Monday by the Massachusetts Gaming Commission. MGM Springfield had its worst.

Encore made a little more than $54M, split between $31.4M from table games and $22.6M from slot machines. MGM brought in less than $19M, split between $5M from table games and $13.9M from slot machines. Slots-only Plainridge Park Casino made $10.2M.

Encore’s revenue numbers in recent months put the casino below Wynn Resorts’ early estimates the resort would bring in $800M in its first year. The casino brought in nearly $314M in gaming revenue between when it opened, June 23, and the end of December.

Industry observers have been surprised at how most of the Everett casino’s gaming revenue has come from table games instead of slots, which are typically more popular at casinos. Wynn Resorts has added more table games as a result of soft slot performance.

MGM Springfield President Michael Mathis told the Boston Globe bad weather played a role in the casino's poor December numbers.