They Make the Calls on How Hot It Is

Ask three people for the time and you’re bound to get three different answers.

So how can you be sure that reports of triple-digit temperatures shattering heat records are really accurate?

Well, you just have to take the word of your faithful weather observer.

“If they say a record temperature was set for the date, you can trust that,” said Gary Ryan, a meteorologist who oversees the National Weather Service’s cooperative observers program.

“You have people who have been keeping records for 30 years,” he said. “These are very reliable people.”

Thousands of amateur meteorologists across the country help the weather service make local forecasts and track long-term global weather patterns by performing a simple, daily ritual: going out into their backyards to look at thermometers.

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There are about 40 weather watchers in Los Angeles County, checking daily high and low temperatures from Torrance to Palmdale and calling in their findings to the weather service.

While some weather wonks have sophisticated computerized observation stations, most are volunteers who stroll outside each afternoon to check thermometers tucked inside birdhouse-style weather instrument shelters.

The observers then call in the day’s high and low temperatures to the Weather Service, which processes the information and sends it to airports, news organizations and anyone else interested in weather data.

But how can the weather service be sure it is getting accurate reports?

“All of the sites are inspected once a year,” Ryan said. “The weather instrument shelters must be six feet off the ground, properly ventilated and away from direct sunlight.”

Though it’s important that the equipment be in proper working order, Ryan said, it’s even more important that observers are consistent and accurate.

“We use their information for forecasts, climatology records, climate trends, rainfall data and flood forecasts,” Ryan said. “They are the heart and soul of the National Weather Service program.”

There are more modern alternatives. Tim Boyle, a weather observer at Cal State Northridge, uses sophisticated computer technology to provide information to the weather service and other agencies. Boyle tracks temperatures, wind speeds, wind direction, humidity and barometric pressure, all without leaving his cubbyhole office.

“The computer picks up weather events all the time and allows me to do deeper analysis of weather patterns,” he said.

But old-fashioned observations still have their place, he said. “We have to go outside to make sure that what the computer is telling us is correct.”

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It appears that weather observers in the San Gabriel, San Fernando, Santa Clarita and Antelope valleys will be calling in some triple-digit high temperatures through the weekend, forecasters said.

“We may get into more seasonable, cooler temperatures at the start of next week and continue through the middle of the week,” Stenson said. “After that, it’s a roll of the dice.”