Great dress - love the strong, dark, bright colors and exposed zip. It doesn't sound like you have too much free time this summer to play, but it has classic shape and lines that should continue to look good for when you DO have discretionary time.
I agree that it has enough color depth to add black tights, or black skinnies, for cooler weather. I just saw a Nordstrom mannequin wearing a similar shape and length dress over skinny capris (like Angie's dress over pants idea?) and it looked chic and current.