It has been very warm in Innsbruck lately and we found a lake! It is called Baggersee. It takes me about 30 minutes to get over there on the bus but it is totally worth it!
The lake is gorgeous and you can still see the mountains with snow on them but it is still warm enough to lay out!
The only thing to be aware of is the occasional bold, older woman that will only sunbathe topless and nearly bottomless.
Something else to be cautious of, I got some sort of sun rash for the first time ever. I have lived in Florida since third grade and had some horrible sunburns but I come to Europe and get sun poisoning? My theory is that I am closer to the sun because I am no longer at sea level and it is more intense even though you cant feel your skin cooking like you can in Florida.
So wear your sunscreen kids! This lake is so worth it!!