Weather in the baltics in May?

Hi Paula. Try weatherbase.com. It shows weather averages (temps, rain, etc.) by month for anywhere in the world. Enjoy your trip!

You can also use wunderground.com (trip planner section) to find actual weather for the past few years for each of your port stops - highs, lows, rain, etc.

Monthly averages for the spring months, unfortunately, aren't very useful in northern Europe, because they can conceal some very large year-to-year fluctuations. My experience during two separate Mays (one in Norway, one in Denmark) was warm and dry weather one year and cold and wet the next.