The Question and Answer section for Incidents in the Life of a Slave Girl is a great resource to ask questions, find answers, and discuss the novel.
The answer to your question would depend upon Harriet's age and the chapter your question pertains to. At the start of the narrative, Harriet is living with her parents. After her mother's death, she lives with her mistress until she also dies. In...
The rains cooled the hot boards underneath where she was sleeping.
In summer the most terrible thunder storms were acceptable, for the rain came through the roof, and I rolled up my bed that it might cool the hot boards under it.
Harriet finally decided that it was necessary to escape when Dr. Flint told her he was going to send her and the children to the plantation.