Question - about painting the garage exterior

Keep it out of extreme heat ( dont do it when its 93 and sunny!) and also check the forecast for the evening. A cloudy day is best as the vehicle evaporates too fast on a hot day. If dew is expected that can compromise the paint job. I have vinyl sided houses I sprayed in the late 90s that still look new. Powerwash first (with TSP or equivalent if needed). If you have any chalkiness at all use Emulsabond or equivalent in your paint. Are you rolling or spraying?