COLUMBIA -- All those scorching 90-degree days this summer appear to be coming with a small reward: A likely break on your South Carolina Electric & Gas power bill.

The Cayce-based utility started a program in mid-July that adjusts monthly power rates if temperatures vary greatly from their 15-year averages.

So the recent near-record average temperatures mean rates dropped in bills that went out last week.

But SCE&G isn't being very specific. Utility officials won't say on average how much bills fell.

And it's unknown how many of SCE&G's 660,000 electric customers in the Midlands and Lowcountry will get rate cuts in their next bills. The utility has 20 different billing cycles for customers spread over a month.

SCE&G did say this July had 23 percent more days where temperatures hit the point that customers cranked up their air conditioning than the 15-year average.

"It has been a hot one," company spokesman Robert Yanity said.

But know this: Any weather-related rate drop would be offset by SCE&G's overall rate increase that started last month to pay for environmental upgrades at power plants.

And one more thing about this new program: Just as an abnormally cold January or way hot July might lower monthly rates under the program, rates could rise in a balmy winter or cool summer.

"It shaves the peaks and valleys," Yanity said of what is known as "weather normalization adjustments."

SCE&G's 310,000 natural gas customers have some experience with this. The utility has used weather adjustments since 1991.

SCE&G started electric normalization adjustments in July as part of a compromise to raise power rates by 4.88 percent over the next two years.

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The trigger for starting the electric weather-related adjustments was the January cold snap, where customers reported bills that were double and triple the usual.

Now with the program in place, customers are hoping for some relief from the heat wave.

But Yanity said SCE&G charges too many different rates to customers to even discuss a range of possible savings in this month's bills.

If there is an adjustment, the difference will be shown on customers' monthly bills. And for the first month, the bill will show the dollar amount shaved due to the adjustment.

But future bills will not be so specific.

Customers will have to do the math themselves by dividing the amount charged for electricity by the number of kilowatt hours used.

Or, Yanity said, they can call customer service.