We will have two full moons in both January and in March this year. When was the last time this occurred?
— Dan Bednarek, Norwood Park, Mike Gayda, Wilmette, Glenn Bailey, Orland Park
Dear Dan, Mike and Glenn,
What do you call a month without a full moon? The answer is February. Dan Joyce, astronomer at Triton College’s Cernan Earth and Space Center, said a full moon repeats every 29.5306 days, and February even in a leap year has just 29 days. Joyce also noted that when February doesn’t have a full moon (like this year), other months must have double full moons and those months are frequently January and March. The last time February had no full moon was in 1999, and after this year upcoming occurrences in Chicago this century are slated for 2037 and 2094. On average, a February without a full moon occurs about four times each century.