Bills are a function of usage, which varies depending on your home and habits. No two homes are exactly alike, and even if similar, they are not operated the same.
Ambient temperature is overwhelmingly the driver of usage and, therefore, the amount on your bill. The hotter and colder it is outside, the more all HVAC units have to work to maintain the desired temperature setting on your thermostat. This is why winter & summer bills are the highest and spring & fall bills are the lowest.
Levelized Billing is a great tool to avoid the ups and downs of monthly billing. Learn more about it on our Payment & Billing Options page.