Krakow vs Riga vs Vilnius vs Tallin for summer

I'm in South Europe at the moment and hitting 20C. So I'm thinking of starting to move to the north in 1-2 months since I'm not a fan of hot weather (30C+).

Which do you think is the best option? I'm in my 30s, looking to be able to roller blade in the city and a good selection of cafes to sit with my laptop. Don't care about food, clubbing, etc.