Not raining but its too hot now

[Grahamm]

I have a textile Air Jacket I picked up from Hein Gericke before they folded and I've always found that comfortable in the hot weather.

There are plenty of similar jackets which have multiple zipped panels to let you control how much ventilation you get depending on the temperature.

I also picked up a goretex overjacket which folds up really small and which I can store in the back pocket or a Kriega bag for those hot days where there's a risk of thunderstorms.