Illuminated Letters

Before our trip to northern Italy, I decided to do some sketchbook preparation. I've been testing which watercolors will match the Italian landscape, sky, and water. I've been taking an on-line lettering class and decided to make some illuminated letters for the names of some of the cities and towns we'll visit. I've tried to show some of the things we'll see in the cities like the prow of a gondola in Venice, striped cathedral pillars in Sienna, gardens in Verona and Vicenza, mosaics in Ravenna, Florentine patterns in Florence, a statue of the first woman university graduate in Padua.

I still need to know: what color is the blue of northern Italy skies?