When I lived in Israel, finding flowers that could withstand the sun for many hours a day was not easy. It turned out the two flowers veranda gardeners could count on were petunias and geraniums. Especially geraniums. If you water them when they get dry — which during an Israeli summer is often twice a day — they will bloom like mad from April until the first rains arrive, typically October. In a bad “rain” year, November or even December.
I never had a huge amount of respect for geraniums until they were the only flower I could grow in those long, dry, hot summers. They rose enormously in my estimation when they turned out to be hardier than most cactus.