I would personally prefer a group fitness class outside. Not as an instructor but as a client. I’m not group fit certified, so I don’t really know much about designing classes.
Just being a prude here, the only thing that I might worry about would be that I can’t be sure that there would be video record of what happened if someone injured his/herself. I’ve got a degree in Justice Studies, so I tend to worry about legal liability a lot. I always want to make sure that I’m covered! It only takes one person to ruin a career!
Although I am a Certified Group Instructor, my first love is Personal Training. I have clients that I train at my gym, but my groups 3 – 10 people are outside. Being in San Diego our weather is near to perfect but I train early morning (30 minute) groups at 5:30a, 6:05a, 6:35a and 60 minute sessions on Saturdays.
You’ll need to do your research first on safety, lightening, location, bathrooms and of course will you need a permit. I would also suggest if you have a permanent location to add them to your Liability as this will go a long way to show that you’re a serious and perfessional instructor.
Much success in 2012!