Hot, humid weather can cause ankles to swell, according to Doctor Tipster. In hot weather, some parts of the body retain water, which is most noticeable in the ankles and feet.
Although swelling is temporary, it can cause discomfort, especially during the summer. Doctor Tipster explains that swelling in the feet and ankles not accompanied by pain is known as peripheral edema. In hot conditions, this swelling is called heat edema and is caused by blood vessels dilating. The condition is worsened by sitting or standing for long periods, and it results in the legs retaining fluid.
Peripheral edema is common, but it is also a serious health condition, according to Doctor Tipster. The condition most likely affects elderly people, pregnant women and people who are overweight.