With red headlights you may see better, but other drivers (and pedestrians) are going to have a harder time seeing you, especially in daytime rain, which is half of their purpose.
Use a red flashlight (or filter) if you need to find stuff in a dark room without waking up the occupants.
And you'd be mad to put one at the front of your bicycle. In poor conditions, most any car driver would logically think the rider is travelling away from them.
(There are quite a few mad people in this world, having said that).
Use a red flashlight (or filter) if you need to find stuff in a dark room without waking up the occupants.