A: Flu is very unpredictable. The exact timing and duration can vary, but influenza activity often begins to increase in October. Most of the time, flu activity peaks between December and February, although activity can last as late as May. Experts aren't sure when this season will peak. Officials were hoping the season had peaked in the first week of January, but the latest data shows activity continued to increase into the second week. Even if flu activity peaks soon, there will probably be many more weeks of flu activity based on patterns of similar seasons when this particular strain has dominated. In those seasons, flu season lasted for at least 11 to 13 more weeks after activity hit the peak. The overall hospitalization rate for the week ending Jan. 13 is now 31.5 per 100,000 people, up from 22.7 per 100,000 the week before.