The correct answer is B. June 1st.
Meteorological summer runs from June 1st to August 31st.
Sunday is not only Father's Day, it's also the first day of the astronomical summer and the longest day of the year.
Here are the results.
A. May 15th - 4% of the vote.
B. June 1st - 53% of the vote.
B. June 20th - 43% of the vote.
Thanks to everyone who guessed! More weather trivia tomorrow.