Posted: 20/08/2014 at 09:21
Hi, Sassibird.....you're not on your with this problem, it's very common.
To save myself the chore of composing a reply, I add this RHS link that explains it very well: https://www.rhs.org.uk/advice/Profile?pid=381
PS. As the nights are now getting cooler, things may improve over the next few weeks.