I started in spring on the chest, I was doing the guts by december (aussie summer). In the peak of Aussie Summer, I didn't go... too hot for me

plus, tattoo artists say NOT to go in the sun. If you get sun burnt and on skin with a fresh tat, you will peel skin and ink and fade your work faster. I personaly don't show off much physically, I use Facebook and upload images of outlines and shade ins. By winter, I begun working on my arms. I'd say feeling the burn of new work under a jacket is annoying. So normal weather is best, too hot or too cold is annoying. So Spring and Autum. If you start in winter, by summer you will actually have 'more' work to 'show off'... so all can be argued, but tattooist say to avoid direct sun UV rays.