Can’t see a laser in daylight.
A green laser would be visible, esp. @ dawn & dusk. I was mostly kidding, since I think it may be illegal except for hog hunting.
I have a Veridian green laser on my Glock 23 and it shows up well enough at the range during the sunny part of the day, at least out as far as my old eyes can see the targets clearly, which is about fifteen yards for pistol practice/drills. A red laser does not show up in bright daylight, at least at the wave lengths and power levels permitted for weapons mounting.