Las Vegas Sun

October 19, 2017

Currently: 75° — Complete forecast

Forecaster: 2008 showed Las Vegas warming up

Heat island effect’ contributed to rise in overall temperatures, says meteorologist


Justin M. Bowen

Construction growth in Las Vegas has led to the city retaining more of its daytime heat into the evening, according to a local meteorologist for the National Weather Service.


  • Quenching Las Vegas' Thirst- See videos, maps and charts and also a five-part series about the region's water needs, what is being done and what the future holds
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Last year, Las Vegas was hotter and drier than normal — and it was the fourth warmest year on record, according to the National Weather Service.

But Andrew Gorelow, a meteorologist for the National Weather Service's Las Vegas office, didn't want to attribute it to global warming.

"Las Vegas is climatologically getting warmer," Gorelow said today. "A lot of that could be attributed to the heat island effect."

The local meteorologist explained that in the desert, the heat of the day dissipates overnight, cooling off temperatures by early morning.

But the building boom during the last decade brought an increase in asphalt roadways and parking lots and also an increase in concrete buildings, which soak up the daytime heat.

"We've had such rapid growth in Las Vegas that the concrete and the buildings and all the man-made structures hold a lot of that heat in at night," Gorelow said. "We don't cool down as much."

The heat island effect, which is common in urban area, can be seen in the morning low temperatures recorded during the year, he said.

"Basically our high temperatures over the last 10 years or so have been average. But what's been increasing are our low temperatures," he said.

Warming up

According to the weather service's annual weather totals, 2008 was the fourth warmest year on record, with low temperatures being the fourth warmest on record.

The average high temperature was 80.7 degrees, an increase of 0.8 of a degree from the normal of 79.9 degrees.

The average low for the year was 59.3 degrees, a 3-degree increase over the normal of 56.3 degrees.

The mean temperature for 2008 was 70 degrees, which was a 1.9 degrees above the normal of 68.1 degrees.

Weather service data showed two days, June 29 and July 8, tied for the highest temperature of the year.

The lowest temperature of the year was 28 degrees, on both Jan. 17 and Dec. 27.

Here are some other weather temperature totals:

• Eleven days were at or dropped below the 32-degree freezing mark. The annual average is 24 days.

• Seventy-seven days reached 100 degrees or higher, compared to the annual average of 72.4 days.

• Seven days had high temperatures of 110 or above, compared with the average of 8.6 days.

• There were no days at or above 115 degrees. The annual average if 0.6 days.

The weather service reported that three high maximum temperature records were tied or broken in 2008 and 25 high minimum temperature records were broken.

There were also four low maximum daily temperature records set. The last time a low minimum temperature record was set in Las Vegas was June 4, 1999, the weather service said.

Drought continues

Precipitation levels were down for the third year in a row, Gorelow said. But it could have been worse.

Through Nov. 30, Las Vegas had been sitting at 1.49 inches for the first 11 months of the year.

"We were pretty much below normal the entire year until we hit December," Gorelow said. "We had quite a bit of rain during the month."

In December alone the city had had 1.15 of an inch of precipitation, including the snowfall in the middle of the month.

The city ended up with 2.64 inches of precipitation by the end of the year, which was 1.85 inches below the normal of 4.49 inches, he said.

He said 2003, 2004 and 2005 were all above normal, while 2006, 2007 and 2008 were all below normal for rainfall.

The greatest 24-hour precipitation total for 2008 was 0.73 of an inch on Dec. 17 at McCarran International Airport. That was the same day the city received 3.6 inches of snow officially. (See the Sun's snow coverage.)

There were also trace amounts of snow recorded at the weather service office on Dec. 15, Dec. 23 and Dec. 25.

Here are more 2008 numbers from the weather service:

• There were 21 days of recorded precipitation (0.01 of an inch or greater) at McCarran, compared to the annual average of 28.6 days.

• For all of 2008, there were 43 days with some precipitation.

• And there were 14 total number of thunderstorm days last year, compared to the annual average of 12 days.

The highest official wind gust for the year was 67 mph on Feb. 13 recorded at McCarran.

Today's forecast

Gorelow said while the local weather office doesn't make long-term predictions, the weather service's climate prediction center shows nothing unusual for 2009 in terms of temperatures or rainfall.

However, today's forecast will be a little warmer than normal. And it could get wet tonight in some areas of the Las Vegas Valley.

Today's high will be 59 degrees, three degrees higher than the normal for today's date. The record high for today is 69 degrees, set in 1997.

There's a 20 percent chance of showers after 10 tonight, along with some gusty winds, the weather service says.

Temperatures will fall to 44 degrees overnight. But Saturday's high will climb to nearly 58 degrees, with north to northwest winds between 10 and 15 mph and gusts as high as 25 mph, the weather service said.

Saturday night's skies will be partly cloudy, with low temperatures in the upper 30s and wind gusts as high as 20 mph in some areas, forecasters said.

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