While the book doesn't directly mention the summer solstice, June 21st is the date of the summer solstice in the Northern Hemisphere. This means that the events of *The Lightning Thief* likely take place during the summer solstice, even if it's not stated directly.
The timing of the summer solstice is significant for a few reasons:
* Maximum daylight: It marks the longest day of the year, with the most daylight hours. This could be relevant to the story, as the Greek gods often associated with light and the sun could be particularly powerful during this time.
* Festivals: The summer solstice is often celebrated with festivals and rituals in various cultures. This could tie into the book's mythological themes and the presence of ancient Greek deities.
Overall, while the book doesn't directly mention the summer solstice, the timing of the story on June 21st suggests a connection to this important astronomical event.