I bought a pair of Novara pants not too long ago and I'm very happy with them. I've been caught in one hard downpour (a couple of light showers) since I got them, and I stayed dry and comfortable. They fold up nicely to go in my backpack if it's expected to rain and are comfortable enough to wear when its not raining. I have worn them on quite a few occasions where it was a little chilly in the morning and expected to warm up a lot by mid-afternoon where I would want to ride home in shorts.

I bought the PI Vagabond jacket (on sale for $45, yay!) shortly after buying the pants and I am very happy with it as well. The vents allow for a lot of breatheability but it will also keep you happy on a cold day (with a good base layer). I have yet to be caught in anything more than a light shower, so I cannot attest for its performance in heavy rain. I image you would get wet in heavy rain as its not a totally waterproof jacket, but waterproof and breatheable jackets are way out of my budget. It has been pretty much the only jacket I have worn since I bought it, where as before I would alternative between different jackets based on temperature/weather. It folds up really nice too.

edit:
Somehow I missed the part about summer heat. I agree with what other's have said, just get wet. I'd rather be soaked from rain than soaked from sweat.