Forecasters are warning of more hot days to come. During heat waves, pot plants become stressed more quickly than plants in garden beds, and your pot plants may not getting as much water as you think. When potting mix dries out, it shrinks slightly away from the edges of the pot, so that when you water, the water runs down this gap while the root ball remains dry. To thoroughly wet potting mix, follow the instructions for watering pot plants in Coping with heat waves, and give your plants the best chance of survival in adverse conditions.
Potting mix can become incredibly hot when pots are in full sun. During extreme heat conditions move pot plants to a cooler spot, including under trees. Grouping them together helps retain humidity around the plants and reduces water loss through the leaves.