According to this site (
Headlight Use Laws for All 50 States | YourMechanic Advice), the states that require headlights on when wipers are on are:
- Arkansas
- California (site says "when it's raining, foggy, snowing, or even cloudy. If you must use your windshield wipers, you are required to have your headlights on")
- Delaware
- DC
- Illinois
- Kansas
- Louisiana
- Maine
- Maryland
- Massachusetts (site says "are turned on")
- Missouri
- New Jersey
- New York (site says "in use or in foggy conditions")
- North Carolina
- Ohio
- Pennsylvania (site says in "continuous or intermittent use")
- Rhode Island
- South Carolina
- Tennessee (site says "continual use")
I started adding the "site says" comments when I noticed different variations.
Additionally, these states say you must have headlights on if it is raining or snowing:
- Georgia
- Michigan
- Minnesota
- New Hampshire
- North Dakota
- Virginia
- West Virginia
(No, I'm not bored at work. Why would you ask?)