Average weather: Summer 2018 brought near normal conditions


The summer weather of June, July and August in North Dakota this year has been so close to average it is almost abnormal, according to Daryl Ritchison, interim director of the North Dakota Agricultural Weather Network.

“We were remarkably average,” he said. “North Dakota doesn’t get close to average commonly.”

More often, North Dakota sees extremes of weather that meteorologists average together over a number of years to determine the normal conditions for the area.

“The NDAWN reporting station 4 miles west of Jamestown was exactly average,” Ritchison said, describing temperatures at the automated reporting station. “Almost all the NDAWN stations in the state were within 1 degree of average.”

The National Weather Service reported Jamestown had an average temperature, calculated by adding together the high and low and dividing by two, of 69.7 degrees in June, 70.4 degrees in July and 66.8 degrees in August.

Precipitation was not as consistent across the area this summer but still came up close to average across the entire state. Annual average rainfall across North Dakota ranges from 13 inches to 20 inches. So far in 2018, Jamestown has received 17.81 inches of precipitation compared to a normal of 14.72 inches for this point in the year.

“The NDAWN station at Jamestown had (reported) 150 percent of average moisture,” Ritchison said. “That is very noticeable and will show up in crop yields.”

Ritchison said most of the area south of Interstate 94 saw above normal precipitation during the summer.

“North of I-94, with some exceptions, they had 70 percent to 85 percent of normal,” he said. “That area spent much of the early summer with half of normal precipitation.”

The state of North Dakota also experienced less severe weather than average this summer.

“Many of the storms were overnight and not the classic evening storm where we get a lot of thunderstorm and tornado warnings,” Ritchison said. “The percentage of the area hit by hail would be lower than average this year.”

The next question for meteorologists is when the first frost will occur.

For Jamestown, it is normally between Sept. 20 and Sept. 30, Ritchison said.

“Northern North Dakota has already hit it,” he said.

The path of Hurricane Florence, still in the middle of the Atlantic Ocean, could play a part in when the southern part of North Dakota hits 32 degrees.

“If it misses (doesn’t make landfall in the United States) it could bring us a trough of cold air,” Ritchison said.

If that does occur, it could mean a first frost date possibly between Sept. 16 and Sept. 20. If Hurricane Florence makes landfall, it would build a high pressure ridge over the region, keeping temperatures higher during that period.

“If we can avoid that first frost, it (frost) could be later than normal,” Ritchison said.