I know for sure that this is not a weather-related issue because it happens any time of year. And it's not related to water usage because I have the same problem whether I've been running my washing machine all morning or if I've turned on the water for the first time at 2 pm. But every day, the hot water doesn't get very hot between 1 and 4 pm. It's warm, but it doesn't get nearly as hot as it does in the morning or the evenings. Is it possible my water heater is on a timer? Is there a cycle it goes through at midday?