We were in both cities at that exact time a few years back, and did carry-on only. The weather alternates between winter and spring. One day is beautiful, and the next one was cool, windy, and rainy. My packable down jacket was perfect, along with a full length packable raincoat, in addition to my layers of tops. The nights were a bit brisk. And of course, you should buy a scarf there, a needed cold- weather accessory, and treasured souvenir. Although we had a great time, I did miss the leaves on the trees and the gardens in bloom.
Have a great trip, and safe travels.