Oregon has many different climate regions, ranging from mid-latitude rain forest to high desert. Areas west of the Cascades are dominated by the Pacific Ocean throughout the year; this brings generally wet, cool winters and warm, dry summers to those areas. To the east of the Cascades, however, lie generallydry areas in the 'rain shadow' of the mountain range. Most of the eastern two-thirds of the state receives less than 15 inches of rain per year, with some areas recording as little as 5 inches. This is in stark contrast to the Coast Range, where some locations approach 200 inches in an average year. Temperature and cloud cover differences between west and east are also quite significant.

This climatic diversity is the primary reason for the complexity of Oregon agricultural practices. The agricultural community has been aware of this for many years and has paid careful attention to climate data and long-term trends.

There are 9 climatic zones in Oregon, 7 of which are used for agricultural purposes and have stations represented in the tables below. Two of Oregon's zones have no stations represented below (Zone 4, The Northern Cascades and Zone 5, The High Plateau) because the relatively high elevations of these zones causes them to be of minor importance in most aspects of agriculture (with the exception of forestry).

The Station History tables below list the locations, elevations, and other pertinent data for the stations in this document. Most of the stations are Agricultural Experiment Stations or National Weather Service offices. The others are public or private agencies who record weather data for the National Weather Service's cooperative observation program.

While this report should answer many climate-related questions regarding various regions in Oregon, more specific information may be needed. Currently there are approximately 250 cooperative stations in Oregon which record daily precipitation and, in many cases, temperature. Additional data sites are operated by several Federal agencies, including the Soil Conservation Service, the Bureau of Land Management, and the U.S. Forest Service. Should the reader require more detailed information for stations in this document or for other locations in Oregon, please contact:

Oregon Climate Service, 316 Strand Ag Hall, Oregon State University, Corvallis, Oregon 97331
Phone: (541) 737-5705, Fax: (541) 737-5710, http://www.ocs.oregonstate.edu, oregon@ocs.oregonstate.edu

We hope that this publication is of use to you. Please contact us if we can be of service.

George H. Taylor
State Climatologist

Stations	Station History	Monthly Means & Extremes Tables (1971-2000)	Total Monthly Precipitation (1971-2000)	Dates of Spring & Fall Low Temperatures (1971-2000)	Evaporation
Burns					N/A
Corvallis
Hood River					N/A
Klamath Falls					N/A
Lakeview					N/A
Madras					N/A
Malheur Exp. Stn.
Medford					N/A
Moro					N/A
North Bend					N/A
N. Willamette Exp. Stn.
Pendleton					N/A
Squaw Butte					N/A
The Dalles					N/A
Tillamook					N/A
Union Exp. Stn.