I have long contended that hair loss in humans was asynchronous, which means that it occurs equally throughout the year; however the article below suggests otherwise, that hair loss may be seasonal. I am not sure from reading this what the article refers to. Are we talking about the normal cycling of the hair that goes into telogen may be more in the summer and fall than other times of the year? This is unclear. If this is the case, the net hair loss would be Zero, but if the article is referring to people with conditions that cause permanent hair loss, then this is another piece of the story that has changed.  Read the article yourself and make your own judgments.