I perform outside all the time. The acoustic situation is different there as you don't have sound bouncing off walls like inside a club or dance hall. You need good monitors outside to hear yourself and especially the band. Having a sound person is invaluable as perceptions of loudness and balance are quite different on stage compared to being out in the crowd. Bright sunlight can make it hard to see some amp controls, tuners, etc. When performing in cold weather, I have a pair of cottton gloves with the fingertips cut off to help keep the hands warmed. Etc. etc. In general, outside is great!