In a Summer Garment contains examples of:
- Afraid of Doctors: Simon hates shiny things coming close to his face. For some time he won't let dentists come near him, although he adjusts eventually.
- Eyes Always Averted: One of the early signs that Simon isn't normal. One of his childhood photos shows a girl trying to get his attention while he stares at the sea over her shoulder.
- It's All My Fault: Before Simon's diagnosis, all Ann "knew" about autism was that it was an emotional disturbance caused by lack of affection. After Simon's diagnosis, she spends some time frantically going over everything she might possibly have done wrong during his infancy. She can't help but be relieved to learn that it's really a handicap of unknown cause.
- Literary Allusion Title: To a passage about holy fools in The Vision of Piers Plowman.For he sent them forth silverless, in a summer garment
Barefoot and breadless, and they beg of none...
- Sensory Overload: Simon screams at the sound of the washing machine, the vacuum cleaner, and crowds of people.