Electric bills for customers in the Houston area can more than double in summer months, mainly because air conditioning. Not coincidentally, electric rates also rise in the summer months because of this increase in demand. The most dramatic rate increases occur in month-to-month plans, but electric rates do increase across the board for all fixed-rate contract lengths.
On the other hand, month-to-month variable rate (no-contract) plans don’t have cancellation fees. You won’t be penalized if you find a better deal elsewhere and want to make another switch.  And, you won’t be stuck paying more than you should be if the market rate for electricity trends down.  But, if it goes up, you’ll be paying more than your in-contract neighbors, and you’ll likely want to shop around again for a better deal.