Climate Data Grapher

Data in the grapher are presented in two forms observed and modeled. Explore the data to learn more about climate trends.

Vermont Climate Data Grapher

* This tool was recently created as a pilot to explore their potential use and value in Vermont. These tools are still under development and we’d appreciate any feedback you can provide to identify errors, share your positive or negative experiences with using the tools, and suggest changes to help improve the tools.

Data Grapher Details and Uses

Observed data: The user can select data  from 2 climate networks and aggregated using 3 landscape scales. The climate data are from Vermont stations in the U.S. Historical Climatology Network or from PRISM data. The landscape selections for aggregating the climate data are by counties, by river basins or for the whole state .  The graph view shows points for observed data values and a solid line for the 5-year running average. The length of the data record varies for each station, with the oldest data going back to 1900.  The aggregated data cover the time period from 1981 to the present.

Modeled data:  Future  climate data for counties, river basins and for the whole state are created from global climate models of the North American Regional Climate Change Assessment Program (NARCCAP). The NARCCAP dataset provides daily values of maximum and minimum temperature and precipitation on a 50 km grid. All future projections cover the period 2041-2070 and are based on relatively high emissions scenarios (SRES A2). Simulations are also generated for the 1971-2000 historical period.  Future and historical simulations are based on four regional climate models (RCMs) nested within at least one of three atmosphere-ocean general circulation models (AOGCMs), yielding a set of seven RCM-AOGCM combinations.

Simulations from these model combinations form the red-blue shaded areas on each graph for the historical and future period.  The top of the red area corresponds to the highest of the seven combinations.  The bottom of the blue area corresponds to the lowest of the seven combinations. The mean of the seven combinations is reflected by the boundary between the blue and red areas.  As with the observed data, a 5-year running mean is used.

The black bar depicts the change between the historical and future modeled averages.

Data Available to Select

The user can select monthly, seasonal, and annual records of the following variables:

  • Daily maximum temperature (F)
  • Daily minimum temperature (F)
  • Daily average temperature (F)
  • Growing degree day accumulation, base 50 F
  • Heating degree day accumulation, base 65 F
  • Cooling degree day accumulation, base 65 F
  • Counts of days with maximum temperature above 90 F
  • Counts of days with maximum temperature above 95 F
  • Counts of days with maximum temperature above 100 F
  • Counts of days with minimum temperature below 0 F
  • Counts of days with minimum temperature below 32 F
  • Total precipitation (inches)
  • Total snowfall (inches; station data only)
  • Maximum daily snow depth (inches; station data only)
  • Counts of days with precipitation greater than 1 inch
  • Counts of days with precipitation greater than 2 inches
  • Counts of days with precipitation greater than 4 inches
  • Counts of days with snow depth greater than 1 inch (station data only)
  • Growing season length (station data only)

Definitions:

Daily average temperature is calculated as Tavg = (Tmax + Tmin)/2 where Tmax and Tmin are the maximum and minimum temperatures in a 24 hour period.

Growing degree day accumulation is the sum of growing degree days (GDD) over the selected time period (annual, season, or month).  A GDD for a day is defined as Tavg – 50.

Heating degree day accumulation is the sum of heating degree days (HDD) over the selected time period (annual, season, or month).  A HDD for a day is defined as 65 - Tavg for days with average temperatures below 65° F. 

Cooling degree day accumulation is the sum of cooling degree days (CDD) over the selected time period (annual, season, or month). A CDD for a day is defined as Tavg – 65 for days with average temperatures above 65° F.

Total precipitation is the total vertical depth of rainfall and/or liquid water equivalent (melted frozen precipitation) of new snow and ice in a specified time period (inches).

Total snowfall is the accumulation of daily snowfall over a specified time period, where daily snowfall is the accumulation of new snow and ice in a 24-hour period prior to melting or settling (inches).

Daily snow depth is total depth of new snow and old snow and ice on the ground, measured once daily (inches).

Daily precipitation is the total vertical depth, in inches, of rainfall and/or liquid water equivalent (melted frozen precipitation) of new snow and ice in a 24 hour period.

Growing season length is the number of consecutive days with minimum temperature above 32° F, from the last spring frost to the first fall frost.