In Garrett County, precipitation is the most important climatic factor. Everyone is aware that plants need a certain amount of precipitation to grow, but rain and snow also contribute to the weathering of rocks and the development of soils.
Garrett County's elevation and location combine to produce a mean annual precipitation of 47.3 inches, an average annual snowfall of 97.0 inches, and the lowest mean annual temperature (47 degrees F) among Maryland's 23 counties. The widely varying topography is also an important factor contributing to marked differences in climate within the county. On the southern facing valleys and slopes, for example, temperatures are generally warmer and precipitation is less than the northern facing areas of the county. These microclimatic differences can produce substantially varying vegetative types.
The period between the last freezing temperature in spring and the first in fall, defined as the growing season, averages only 122 days. However, this average can vary by as much as two weeks from place to place along the river corridor. This fact further influences the vegetative types found in this region.
- Most of the reports can be found on the document archives of the Deep Creek Watershed Management Plan work.