Can I put off changing my snow tires one more week? Should I stock up an extra cord of firewood? When can I plant my peas? All questions motivated by predicting the weather and all questions that Russ Qualls, Idaho State Climatologist and UI biological and agricultural engineering faculty member, has been asked at one time or another.

Qualls, guardian of Idaho’s historical climate records, is quick to point out that climate is not weather, and it is not meteorology. “Climate is the weather that was,” meaning climate is weather trends or extremes of any region. “People often confuse weather and climate.”

Idaho’s data collection began in 1860s territorial days
When it comes to climate, Qualls can supply official historical weather data from the early 1860s, when Idaho was just a territory. The earliest weather records in what is now Idaho were collected by the Lewis & Clark expeditions, but those were not climate records, since they were collected at various locations, and the expedition was seldom at any one place for more than two consecutive days.

Prior to the War of 1812, personal weather diaries were the primary sources of United States weather information. Earliest U.S. weather records began with an 1814 government directive to the U.S. Army Surgeon General that data be gathered by the medical corps at forts and barracks across the country. The data were gathered and kept by Army surgeons.

Qualls is keeper of Idaho territory climate books documented for decades at Fort Sherman, where North Idaho College now sits. Similar books exist elsewhere from this time period at Fort Boise, Albion, and Camp Lyon on the Oregon border. Perfectly hand-scripted pages look like a style guide from Palmer’s method of writing, with every letter perfectly formed in pen and ink.

Army surgeons typically focused on air temperature and precipitation. Additional remarks included comments like “snow, light fall, not measurable,” or “precipitation in form of rain and hail.” One notation offered, “No observations, went moose hunting.” Another entry: “Small pox.”

Collection instruments little changed—a can will do
Precipitation was measured in a can open at the top. A measuring stick calculated liquid collected to the nearest 1/100th of an inch. This has not changed in 145 years. Where the can is sited is more important than the type of can used—clear view sky, vegetation around it, but not enough to create a rain shadow.

Temperature at forts was measured with a mercury-in-glass thermometer designed with two tubes, one to record and hold a maximum and the other a minimum temperature. Observations were normally made daily, and sometimes recorded at specific times. At Fort Sherman, temperatures were recorded at 7 a.m., 2 p.m. and 9 p.m. After each reading, the thermometer was shaken down for the next observation. Temperatures were kept to the nearest one degree Fahrenheit.

Now mercury or liquid-in-glass thermometers are being replaced by electronic instruments that read and record air temperatures. Rain-collecting devices have been redesigned and electronically automated, but still employ the basic open-can-collecting principle.

The accuracy of today’s instruments is often subject to the same primary uncertainty of instruments 150 years ago. Human, natural, and instrumental variables, such as measurement timing, air movement, and instrument site placement and calibration can be problematic. Wind in particular affects that ability of a rain gage to capture the falling rain, snow, and hail.

In 1890, the national weather program was transferred to the U.S. Department of Agriculture, where it remained for 50 years before shifting to the Department of Commerce.

Myron Molnau, Idaho’s first climate historian
Modern day weather collections and records were kept by the Federal Climate Service, with branches in every state, until 1973, when it was discontinued, virtually overnight.

University of Idaho agricultural engineer and professor Myron Molnau, with an education in climate studies and a passion for weather, stepped forward. He helped organize the American Association of State Climatologists, and he established the Idaho State Climate Services (ISCS), with the principal mission of archiving and disseminating climate data for Idaho.

Molnau, Idaho’s first state climatologist, for over 20 years devoted long hours to centralizing Idaho’s historical weather data, establishing weather stations throughout the state, and creating an Internet database that has put historical and current weather data as close as the nearest computer.

Today numerous agencies collect weather records for various purposes throughout Idaho. Weather records archived in ISCS come primarily from the National Weather Service Cooperative Observer Network, or COOP stations, where volunteers collect and maintain records for the NWS. The oldest continuous station in Idaho is at the UI Plant Science Farm in Latah County, with archived records beginning in 1893, just four years after the county was created by an act of Congress to establish the land grant university for Idaho Territory.

What is ‘normal’ weather?
When that favorite TV weatherperson tells you the monthly precipitation and temperature is above or below normal, he/she is comparing current measurements to local measurements averaged over the most recent three-decade period, currently 1971 to 2000. Averaging periods much shorter than this become subject to temporary fluctuations.

If averaging covered 100 years, the temperature might be reported as “above normal” for 30 years running. Although there are more scientific reasons, a normal range of human experience extends back a generation, so it makes sense to compare this year’s weather with the recent three decade average to set the context of “wet or dry” and “hot or cold.”

The global “Little Ice Age,” which ended in the early 1880s, was followed by a period of warming until the early 1940s, which was succeeded by a 30-year cooling trend, and has now given way to another warming period.
The ISCS has historical data from a total 241 stations; however the service currently archives ongoing data from 126 stations, including most UI Research and Extension Centers.

Idaho’s most extreme temperature records were observed at two stations—the lowest of minus-60°F at Island Park in 1943 and highest, 118°F, from Orofino in 1934.

Idaho’s historical data is available at Idaho State Climate Services, www.uidaho.edu/~climate. Select daily data/Idaho daily data. If you have questions on how to use the data, try the tutorial at the Idaho daily data URL, or call the UI climate lab at 208.885.7004

Contact Russ Qualls at rqualls@uidaho.edu or Myron Molnau at myron@uidaho.edu.