Nedda Gilbert, MSW, Educational Consultant, and Author
It's tough to answer this kind of question without more information. If I was to make a guess - and it's only a guess - working with your 3.6 GPA, I would say yes to Union College - likely to Connecticut College, and maybe to Skidmore. I wish your GPA was a tad higher to wow them. However a 3.6 is pretty terrific.
You don't say if you are currently a freshman or a sophomore. That would be helpful to know. It would also be helpful to know what kind of classes you took to score that 3.6. Hard core classes in the humanities, sciences, or math would earn respect and be looked at favorably. A roster of electives like Film and Ambient Sound would be less impressive.
Your probability of winning admissions will also be impacted by your high school record. If you're finishing up your freshman year, all three of these schools will require you to submit your high school transcript as well. Unfortunately, that has to follow you at this point. Skidmore and Union will also want to see your most current SAT or ACT scores. I don't believe Connecticut College requires test scores.
You also don't say why you want to transfer. It could be the major and academic focus, or the campus culture and students. My guess is you now want a more competitive and highly ranked school. Perhaps your grades and scores coming out of high school made these schools out of reach. If that's the case, the 3.6 may do the trick. More importantly, a persuasive essay on why you want to transfer, and why to that school in particular will be critical to whether you're admitted or not. If the 3.6 is an uptick from your performance in high school - that's exactly what the colleges want to see - your maturity, how you've grown, and that you're a solid, sure-footed student. A really compelling essay and story about where you were then, and where you are now could help seal the deal.
Unfortunately, without more details, I don't think I have enough to guide you further. You're getting somewhat lukewarm advice here. I'm inviting you to write back and let us know a bit more about your decision to transfer, and also your high school record. I'd be happy to jump back in. Hope to hear from you!