Water pump running longer during the night

According to Rocky Mountain Power, the temperature during June was about 8 or 9 degrees hotter than it was in 2014. This means that my air conditioner ran more than normal during June, and it also means that my sprinkling system ran more during the night. Usually during June, I would run the sprinkler about four hours, but I've been running it for six hours. I don't remember the HP of the pump, but it is a hefty motor and draws significant current, probably close to as much as the A/C. If July cools down to normal, I may find that my electrical costs go down, causing my excess solar power to increase. In the past, August was the big month for electrical costs, and it will be interesting to see what the temperature is this year during August.