When is it too hot to fish?
So I get the theory... Pike should be a no-go in summer (I've not actually targeted them at all in the 7 or so years I've been fishing). Barbel (especially) and Chub struggle to go back in summer if not well rested.
And there's all sorts of infographics out there giving species-by-species breakdowns of water temperature and fish oxygen deprivation.
But for you personally, when do you say "enough is enough" and decide not to head for the banks for inland fishing?
Today it reached 25C here. Wasn't too bad when I first got to the local river (overcast and faintest of drizzle) but eventually warmed up and I'm now sporting a smidge of a sunburn. I planned a mobile day so didn't take a brolly with me, so resorted to finding as much shade as I could (but obviously wasn't enough!). The fish were active, just not interested in eating (I tried luncheon meat, spicy halibut pellet, bread, pickled cockles as an experiment as everyone has been raving about them) but still swam up to investigate loose feed (but again, didn't actually nibble on any freebies). Real shame as amongst the (guesstimated) 3-4 lb chub there were some 6lbers and the odd 8lb+ barbel (which would have been my first).