How Hearst Castle adapts during hot weather to protect visitors and artifacts

At Hearst Castle, there are numerous historic items on display but as temperatures warm up, staff says it’s important the doors remain closed to help protect those pieces.

“They set humidifiers, dehumidifiers, they position fans, and they keep the air circulating. We try to keep the collection between 45 and 55 relative humidity,” said Cara O’Brien, museum director.

O’Brien says it’s not just the museum pieces they’re concerned about. They have adapted their tour routes for visitors, adding misters from the trees as well as umbrella shades and fans in every room in the castle.

“You can observe the tour guide has moved the group to take advantage of the natural shade and throughout the day, we’ll use umbrellas and shady spots to ensure our guests are comfortable,” O’Brien said.

Some visitors to Hearst Castle on Thursday were shocked by how much the temperature changed from the visitor center to the hilltop. Emily Stafford and her family are visiting the castle for the first time and says she isn’t used to the heat being from the United Kingdom.

“It was like 20 degrees cooler down here and up there it was very hot. You need water,” Stafford said.

“You’ll arrive down at the visitor center and you’ll think, 'Oh it’s a little bit chilly and foggy, I’m going to bring my sweater,' and then you arrive on the hilltop, if you didn’t see the extreme heat warning sign, and it's 100 degrees,” O’Brien said.

Doors are also closed once it starts getting hot.

“We flush out the hot air for as long as we can but as soon as the outside air is getting warmer than the inside then we equalize and shut it down,” O’Brien said.

Summer is a busy season at Hearst Castle. The castle sees around 3,000 people daily with tours every 10 minutes. O’Brien says they dump out water from the dehumidifiers twice a day.

“We do a lot of subtracting moisture because the guests that come through... we’re putting off moisture so it’s warm. Our bodies are trying to cool us. There are enough people going through to raise the humidity,” O’Brien said.

Some items need to be preserved in cool temperatures, including the textiles.

“If they did get wet, they could attract dirt and moisture and that could attract pests so that’s why it’s so essential to control humidity for our textiles,” O’Brien said.

Staff also actively monitors the visitors as well as other staff.

“If a supervisor sees that somebody is extra tired, they’re going to go and take the tour for them or sub someone else in,” O’Brien said.