The days in the summer are gloriously long, but the risk of frost still holds until the end of May. I've got another month to go before I can put tender things out. Plants that are not frost hardy have to be kept in polytunnels and greenhouses until then. If we get a late frost, those places really should have a heat source.
There is also a mouse problem! When carrying in the new plants, I saw to my horror that mice had climbed up and eaten a lot of seedlings and germinated seeds.