It was a sizzling September to remember

Recent polls suggest a deep divide over the issue of climate change, so it's easy to imagine the arguments that might break out over news like this: Nevada just experienced its hottest September since people started keeping records of such things almost 115 years ago.

According to the Western Regional Climate Center in Reno, last month's statewide average temperature of 66 degrees was the highest on record, edging out the old mark by six-tenths of a degree.

It was also 6 full degrees warmer than normal for September, said Michelle Breckner, a climatologist for the federally run climate center.

"See? See?" global warming believers will say.

But it's not exactly a trend, Breckner said. June was unusually hot this year, but July and August were cooler than they have been for the past several years.

Then there is this: The old record for September was set clear back in 1935, 121/2 years before Al Gore was even born, and it was followed up three years later by what still ranks as the fourth hottest September ever.

"Ah ha!" climate change deniers will shout.

Yes, but consider this: In Las Vegas, the average high temperature last month was 97.3 degrees, 3.5 degrees above normal for September.

And it was definitely a dry heat. Not a single drop was collected by the official rain gauge at McCarran International Airport last month.

Even so, the unusually warm conditions did not result in a spike in demand for electricity.

"Things were pretty much business as usual for us," said Chelsie Campbell, spokeswoman for NV Energy.

Water deliveries did tick up slightly in September, but Las Vegas Valley Water District spokesman J.C. Davis said going from an average of 349.5 million gallons per day last year to 350.1 million gallons a day this year is "what you call a statistically insignificant change."

The warmer weather did present a marketing challenge for local water officials since Sept. 1 marks the beginning of the fall water schedule, when sprinkler use is restricted to three assigned days a week.

"It is a really difficult thing," Davis said. "We're telling people that it's fall and it's time to cut back, but they walk outside and the soles of their shoes melt."

The statewide average is compiled using temperature readings from about 60 different weather stations across Nevada.

Breckner said all of the stations used have climate records going back at least 30 years.

A few of them, including the original station in the Las Vegas Valley, started collecting weather data in 1895.

Then Breckner said something shocking: "All and all, we are warming."

"Say what?" the naysayers will ask.

There is an overall warming trend, she said, but at least some of that is because cities are growing, and that's where the weather stations are.

"It's the urban heat-island effect. There's just more pavement on the ground, and that's heating things up. More pavement and less trees," she said.

"Oh," warming enthusiasts will say, a little dejectedly.

Ultimately, Breckner cautioned against reading too much into one record set in a single month. After all, the calendar is a human creation. The sun and the seasons and the orbiting Earth don't care what day or month it is.

"There's always more to the story," Breckner said, adding that what really separates a record month from a normal one is how many storm systems blow through to cool the state down.

So to recap, last month was the hottest September on record, but that by itself doesn't seem to say anything one way or another about climate change. Or maybe it does.

Just don't ask Breckner to weigh in on it.

"There's a lot of controversy about global warming," she said with a nervous chuckle. "That's a whole other ball of wax."

"Yes," the climate debaters will say, "but is that ball of wax melting?"

Contact reporter Henry Brean at hbrean@reviewjournal.com or 702-383-0350.