Light Extinguishes Fire

Look, you see, if you're trying to light a fire in daylight you can't see the flames as well as you can when it's night.
This explains why it's harder to light a bonfire in the daytime. Also light makes the fire burn with a lot more smoke, so it's always better to turn off the lights and draw the curtains when lighting a fire, because you'll get a much warmer and cleaner burn.
How many times do you find a bonfire that was burning perfectly well the night before, just a pile of smouldering ashes the following day?
That proves that light not only makes fires burn colder and smokier, but also extinguishes them.
This also explains why the light of the flames from a bonfire can cause itself to be extinguished a lot faster...