It's the climate changes

The bridge which carries Oregon 62 over the Rogue River at Shady Cove washed out shortly after 8 p.m. on Tuesday, Dec. 22, 1964. (Knackstedt photo)

We love the Rogue Valley for its mostly mild climate, but that doesn't mean we haven't seen extreme weather.

The one thing that really stands out about our weather is summer heat. Every year we expect to roast in triple-digit temperatures sometime before Labor Day. Our record high temperature has been at least 100 degrees on every day of the calendar from June 14 all the way through Sept. 19, and there have been 100-degree days as early as May 6 (1987) and as late as Sept. 27 (2003).

Medford weather extremes

Highest temperature: 115 degrees, July 20, 1946

Worst hot spell: 1981

Aug. 7: 111 degrees

Aug. 8: 114 degrees

Aug 9: 111 degrees

Aug. 10: 110 degrees

Coldest temperature: -10 degrees, Dec. 13, 1919

Worst cold spell: 1972

Dec. 7: 1 degree

Dec. 8: -6 degrees

Dec. 9: -6 degrees

Dec. 10: -6 degrees

Dec. 11: -3 degrees

Most 24-hour precipitation: 3.75 inches, Dec. 21-22, 1964

Wettest month: December, 1964, 12.72 inches

Wettest year: 1996, 31.41 inches

Driest year: 1959, 10.42 inches

Greatest snowfall in one season: 31.6 inches, winter of 1955-56

Sometimes things really warm up. Medford's hottest day ever was July 20, 1946, when the official National Weather Service thermometer read 115 degrees.

Some particular days of the year are hotter than others. July 27 has the highest average daily temperature, 93 degrees, and there have been at least 20 years when that date saw triple-digit heat. So if you can't stand the heat, don't plan a barbecue for July 27. (It's on a Wednesday this summer.)

When it comes to winter cold, we're lightweights compared to Chicago and Detroit, but nobody would ever accuse us of being tropical. A hard freeze comes every few years when temperatures drop down to single digits, and during December 1972, Medford shivered through four consecutive nights of below-zero cold. Our coldest night ever came back in 1919, when the mercury plunged to minus 10 in Medford on Dec. 13.

When we talk about weather extremes in Southern Oregon, we use Medford data, because that's where the National Weather Service office has been measuring temperatures and precipitation for nearly 100 years. Anyone who has lived here for any length of time knows how much the weather varies across the region.

A winter storm might drop several inches of snow at an elevation of 2,000 feet, but folks who live on the valley floor would never see a flake.

A 105-degree scorcher in Medford might be no more than a sweaty 90 on a north-facing slope in the foothills.

We can thank our proximity to the Pacific Ocean for our generally moderate weather. Even though we're some 60 miles from the sea, that's still close enough for its vast expanse of cold water to temper our highs and lows — at least most of the time. Our temperature extremes — the record breakers — often stretch across several days, when atmospheric conditions interrupt the regular flow of cool, relatively dry air from the Pacific Ocean.

Our spot on the globe helps, too. Southern Oregon lies near 42 degrees north latitude, a place that tends toward mild weather, says Brett Lutz, a weather service meteorologist in Medford.

"As you go across the country, (latitude 42) tends to be pretty moderate," Lutz says.

Hot spells develop when high pressure air settles in, and the heat can linger for days or weeks when the air mass collects heat. Those are the days when records are made, such as the 115-degree day in 1946. The worst extended heat wave came more recently, during the summer of 1981. From Aug. 7 to Aug. 10, Medford's daily high temperatures were 111, 114, 111 and 110. Forest fires burned near Gold Hill and in the Applegate Valley that week, and it seemed like the whole region could ignite at any moment.

Our coldest winter nights occur when cold air pours down out of Canada and blocks the flow of warmer marine air. That's what happened in December 1919 and again in December 1972, when the mercury fell to minus 6 on Dec. 8, 9 and 10. On Dec. 11 of that year, the low was minus 3, and on Dec. 7 the low was 1 degree, for a total of five long nights of bitter cold.

If there's snow on the ground, the cold only gets worse, says Chuck Glaser, who's worked at the local weather service station since 1973 — longer than anybody else. The year 1919 saw Medford's biggest snowfall ever — 11 inches on Dec. 11 — and two days later, thermometers downtown read that record 10 below zero.

Those nights are exceedingly rare, however. "We can go a long time between single-digit (cold spells)," Glaser says.

The mountains between the Rogue Valley and the coast force storm clouds to drop much of their moisture before they reach Medford, so our rainy extremes aren't much to write home about. But we've had our moments. On May 18, 1956, 1.4 inches of rain fell in Medford in just one hour — the record for most precipitation in 60 minutes. Still, that's not much more than a drop in the bucket compared to the national one-hour record — 12 inches at Kilauea sugar plantation in Hawaii in January 1956, according to weather service records.

The big rain that old timers still talk about came in December 1964, when nearly 4 inches drenched Medford in 24 hours — the prelude to a flood that washed out bridges and swept away homes from Shady Cove to Grants Pass. During a 24-hour period that spanned parts of Dec. 21 and 22, Medford had 3.75 inches of rain. The deluge melted low-elevation snowpack across the region, and the Rogue River ran wild for several days around Christmas.

Our annual precipitation figures reflect our dry Mediterranean climate. Medford typically receives just 17 to 18 inches of rain per year — not much compared to most of Western Oregon. Even our wettest calendar year, 1996, brought just 31.41 inches of rain. Our driest year, 1959, saw 10.42 inches of precipitation at the Medford airport.

Our mild winters make us the envy of folks who live in icy climes, but they don't offer much opportunity for snow play — at least on the valley floor. For serious snow, we go to the mountains, especially Crater Lake, where a memorable storm in mid-March 1975 dropped 119 inches (nearly 10 feet) of snow between March 16 and 25.

The region's weather extremes make for good stories, but the truth is the climate here is mild compared to much of the continental United States.

"It's just a very nice place to live," Glaser says.

Bill Kettler is a freelance writer and former Mail Tribune reporter living in Rogue River. Reach him at bdkettler@gmail.com.


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