Summary of 10-Year (1989-98) Weather Patterns for Grants Pass, Oregon

Yearly and long-term weather patterns have major effects on forest ecosystems of the Applegate AMA.  Precipitation amounts combined with maximum and minimum temperatures can affect growth and survival of all biological systems.  Often, success of our forest and resource management projects (e.g., plantings survival and growth, noxious weed treatments, and fish & wildlife habitat improvements) hinges on having the "right" weather.  A review of past weather patterns and their affect on our forest management projects may provide insights into the weather patterns conducive to successful projects.  In this paper, I provide a short summary of precipitation and temperature data for Grants Pass, Oregon.  Although not presented here, I have available the same data for Ashland and Medford.

Long Term Averages (1928-98):

• The average maximum temperature = 68.5 degrees (F).
• The average minimum temperature = 40.8 degrees (F).
• The average total annual precipitation = 30.88 inches.

Highlights (1989-90):

• 1990 was a hot, dry year; precipitation was below average and temperatures were above average.
• 1994 was a dry, cold year; precipitation was below average and temperatures were below average.
• 1989-91 & 94 were years of below average precipitation.
• 1995, 96, & 98 were years of above average precipitation.