Latest Score:


in 2019

Weight: 8%
score trend is flat over time

Water is essential to a healthy forested ecosystem, but excess water can lead to flooding and disease outbreaks, while a deficiency can lead to drought1. For example, extreme rain events can cause flooding in low-lying areas, but even upland forests may experience “overland flow”. This occurs when rainfall is so heavy that it cannot be absorbed into the soil. Aquifers are not replenished and soil erosion may happen, exposing tree roots and washing away nutrients. Fluctuations in rainfall above or below the long-term mean will lead to stressful conditions for some forest species while creating ideal conditions for other species. Trees are adapted to the long-term conditions they have experienced, therefore deviations in precipitation from the long-term mean (both above and below) could be problematic to forests. Ideally, a healthy forest ecosystem has water availability that remains consistent. Total annual precipitation is the sum of all water (in the form of rain, snow, or ice) that fell within a calendar year for Vermont.  A high score means that precipitation levels are near the long-term mean.

1Rustad, L., Campbell, J., Dukes, J.S., Huntington, T., Lambert, K.F., Mohan, J. and Rodenhouse, N., 2012. Changing climate, changing forests: The impacts of climate change on forests of the northeastern United States and eastern Canada.

Annual precipitation is expected to slightly increase, but the largest change will be in the intensity and occurrence of extreme precipitation events. Extreme, flood producing, events are increasing, where a large amount of precipitation falls in a short amount of time. This can cause soils to wash out, and a large amount of runoff, with less water absorbed by the soil. Short-term summer and fall droughts are expected to increase. Lack of moisture during the growing season can harm the health of trees.

Additional Resources

National Climate Assessment 2014

National Climate Assessment 2018

NCEI State Summary for VT

Interpretation provided by:

NOAA, Northeast Regional Climate Center at Cornell University (2020)


The score is calculated using a target value and the historical range of the the entire long-term dataset. The higher the score, the closer this year's value is to the target.

Once the score is computed for each year, the trend in scores over time is calculated. If the trend is significantly positive or negative, the long-term trend is marked as increasing or decreasing respectively.

Component Description
Scored as

Distance away from long-term mean (scaled 1-5)

Target value

Long-term mean

Directionality of scores

No change from the long-term mean is better.

Minimum value used in scoring

Data minimum - 10% of range

Maximum value used in scoring

Data maximum + 10% of range

Data of annual total precipitation (inches) for Vermont were collected from NOAA National Centers for Environmental Information1. We set the target for the dataset as the total precipitation from 1961-1990 which is used as the baseline normal for climate comparisons by the Intergovernmental Panel on Climate Change (IPCC). The current year is scored for where it falls between the target and the upper scoring bounds (maximum value in the dataset) or the lower scoring bounds (minimum value in the dataset), scaled to be between 1 and 5.

1 NOAA National Centers for Environmental Information. 2019. Available at: