Monday at noon, a bank sign on Midway Boulevard in Oak Harbor said it was 84 degrees. But according to the National Weather Service, the temperature in the city was a mere 66 degrees.

It’s an odd phenomenon that hasn’t gone undetected. North Whidbey resident Glenn Eckard noticed that “Seattle weatherpeople” regularly report temperatures in Oak Harbor 10 or 20 degree below what residents are experiencing. He surmised, tongue firmly in cheek, that there must be an ice cave somewhere in the city.

“I’ve asked a couple of them where’s the cave but they won’t tell me,” he wrote in an email to the News-Times. “Could you find out and let me know?”

Doug McDonnal, a meteorologist with the National Weather Service in Seattle, isn’t aware of any hidden ice caves, but he knows that temperatures in Oak Harbor are usually reported to be lower than surrounding communities.

“We certainly notice that Oak Harbor always stands out as one of the cool spots in Western Washington,” he said.

McDonnal said the reason is probably due to the thermometer location, which is on Whidbey Island Naval Air Station. More than likely, he said, it’s exposed to cool marine air.

Petty Officer Amy Sexton with the Navy’s aviation weather department said the automated weather sensor is, indeed, located near the water, at the end of a runway. She said a breeze off the water keeps the whole area cool.

In comparison, McDonnal said the thermometers on bank signs read notoriously high. They are often located in the sun, surrounded by hot pavement and have little air movement around them. It’s probably the temperature a person would feel if he or she stood next to the sign, but it’s not the way official readings are taken.

The thermometers used by the National Weather Service have to be in the open shade, in an area with plenty of air movement and six feet off the ground.

McDonnal said temperatures within the city of Oak Harbor are probably warmer than those at the Navy base for the same reasons. The pavement in the city warms the air and the buildings cut down on the breeze.

Yet both McDonnal and Sexton said there should only be a few degrees of difference between the base and the city, not the 10 to 20 degrees residents notice. The weather service, for example, reported the temperature had jumped to 71 degrees by 2 p.m. Monday, but the KING TV “weather station” at Oak Harbor Elementary School listed 86 degrees at the same time.

The weather service predicts the scorching will continue in Western Washington over the next few days, likely breaking records.

Johnny Burg, another meteorologist with the National Weather Service, said the records for Oak Harbor are pretty sparse, so they don’t know if temperature records are being broken.

In Coupeville, however, the records go back to 1895. The record high for July 29 was 92 degrees in 1960; the record for July 30 was 90 degrees in 2003.

“There might be a good chance that those records will be broken,” he said.