The table and chairs are most definitely a patio set. In Kit's story, she throws her birthday party in the family's backyard, and she uses the table and chairs to serve food, etc. And, as happymargaret said, Kit's mother also was a member of the garden club, which of course took place in the garden, where the chairs were most likely used.
I actually found very similar sunburst chairs at an estate sale (they were white, not green though). Unfortunately they sold before I could get my hands on one!
The OllyMolly family just got bigger! Welcome home, Saige and Olivia!
The Excellent Eleven: Kit, Ruthie, Felicity, Elizabeth, Rosie (#37), Molly, Teddy (Mckenna), Caroline, Kirsten, Saige, and Olivia (#40)