MILAN, Minn. >> A Minnesota family is marking 125 years measuring the temperature and taking precipitation readings for the National Weather Service, which officials say is the longest running record for a weather observing family in the state.

The Opjorden family in Milan began voluntarily taking measurements in 1893, Minnesota Public Radio reported. The practice has now spanned three generations.

“It’s basically the gold standard of a climate record,” said Michelle Margraf, who leads the National Weather Service’s observing program in the Twin Cities.

Only about eight weather observation sites in the U.S. have operated for so long, she said.

The family was awarded the Family Heritage Award by the National Weather Service on Dec. 11. Sen. Amy Klobuchar also thanked the family for their work in a letter.

“It’s just amazing, the dedication that they’ve had,” Margraf said. “We are so grateful to them for this precious archive of weather data.”

The consistent measurements help researchers observe how the climate is changing, Margraf said.

“If we have that steady weather station in one location, you can go back and look over time to see how the weather has changed,” she said. “And looking at that record, the state climate office has determined that the temperature over that period of time has risen, on average, about 2 degrees.”

The farm in Milan has seen its biggest changes to the daily low temperatures in summer and winter. The farm has also seen an increase in precipitation.