Nottingham Cottage lacks air conditioning, according to Us Weekly, and “Kate was getting really hot and bothered at home so she thought she’d get away for a few days,” a source told the UK Mirror.
Story continues below slideshow
The "insider" also said Kate “wanted to spend what will probably be her last weekend before the baby is born having a normal time with her family.”
Meanwhile, the Duke of Cambridge and brother Prince Harry took part in the Jerudong Trophy, an annual charity polo match, in Cirecester, England on Sunday.
William was conflicted about whether he should attend the event, nearly 100 miles from London, where his wife plans to give birth, according to the Daily Mail. But Duchess Kate could rest easy knowing that if she went into labour, Will would have used a police escort to join her post-haste.
Numerous reports pegged Catherine's due date as July 13, although Buckingham Palace would only say the baby was due in mid-July. With the 13th come and gone, Will, Kate and their fans will have to wait a bit longer for the new prince or princess to arrive.
See photos of William and Harry at the polo match below: