There are two ways to beat the heat in July and August: Expose more skin (not recommended) or make your clothes lighter and more flowy. UN Ambassador Susan E. Rice chose the latter:
"Mint green pantsuit" doesn't sound like a great choice. But I'm hard pressed to dislike this outfit. It fits well and the colors work for her. Most of all she looks comfortable. Not "I feel like I'm wearing my pajamas comfortable" but rather comfortable in her own skin, with her own look. Sometimes that's the most important thing: know your style. It sort of reminds me of Rosa DeLauro.