"on" is used for dates (e.g. "on Monday", "on Christmas day", "on September 10th")
"at" is used for times (e.g. "at 5:00 PM", "at midnight", "at noon")
"in" is used for weeks, months, years, and seasons (e.g. "I want to visit Canada in the winter", "I plan on going skiing in December", "I went to Spain in 2012")
in summer
Объяснение:
"in summer".
"on" is used for dates (e.g. "on Monday", "on Christmas day", "on September 10th")
"at" is used for times (e.g. "at 5:00 PM", "at midnight", "at noon")
"in" is used for weeks, months, years, and seasons (e.g. "I want to visit Canada in the winter", "I plan on going skiing in December", "I went to Spain in 2012")