June 21, when the sun is at its northernmost point
"On midsummer day, we woke up early to watch the sun reach its highest point in the sky before heading out for a picnic."
The period around the summer solstice; about 21st June in the northern hemisphere.
"The long daylight hours of midsummer made it difficult to tell exactly when night had fallen."
Happening in the middle of summer.
"The festival takes place on midsummer night, just as the sun reaches its peak warmth for the season."
A pagan holiday and Wiccan Sabbat.
"The coven gathered in the meadow to celebrate midsummer, marking their traditional Wiccan sabbat of longest day."