A study of 102 women found that seasonal changes can play a role in the timing of menopause. When questioned about when they had their last monthly period, 30 remembered only the season of the year, but 72 recalled the exact month. March, April, and June were cited the most often, and August and December the least often, according to the results reported in the on-line journal Human Reproduction (June 9, 2004).
The investigators recommended more research into factors that can influence the start of menopause, including the role of the hormone melatonin. Also, internal and external factors affected by conditions such as length of day and temperature can have an impact on the ovaries.