Congested??

My 7-month old baby gets congested whenever I take him outside for a stroll.... yesterday it was nice weather, so I put him in his stroller (he's still in the carseat in the stroller) with a light blanket.... and then all night he was fussing because he was so congested.... Seems to happen everytime. I'm surprised that he's so sensitive to a tiny breeze! How will I ever take him outside in nice weather? Anyone else experience this?