In the United States, the influenza (flu) season is considered October through May, usually peaking in February. The best way to protect yourself is to wash hands with soap often, and to keep hands away from your face. Another method, effective for some, is to get a flu shot. The Centers for Disease Control recommends that all persons over age 6 months get the vaccine.
Here's an infographic on influenza:
Here's hoping that you and yours stay healthy this flu season!