Don't think of it as too hot to run in now brimps, think of it as acclimatisation!
Got out for a four miler yesterday and ran six this morning. I knew I wouldn't last all week! Very warm though, it's a bit of a shock to the system when there's no showers to run through or water stations at every mile.
TT the 'other' 3:30 thread (Minni vs Dubai Dave) is still very busy with running banter, maybe worth popping over. I think it's just going to keep on going so good for if you're targetting 3:30 at Amsterdam. I'm a bit jealous you're planning that as your Autumn marathon, I had a blast last year and will likely do it again once I've ticked off all the others I want to do!