Future Differences from "Normal" Temperature
An interactive data tool exploring how the changing definition of a climate normal affects our interpretation of future climate changes.
Average Annual Cold Days
Average Annual Number of Days with Cold Low Temperatures
This tool is excerpted from Mid-Atlantic Regional Climate Impacts Summary and Outlook: Winter 2022–2023.
Tool Background
Similar to earlier climate tools that focused on extreme heat, cold low temperatures are also projected to warm over time. Warmer winter lows can lead to fewer freezes, contributing to the incidence of earlier springtime weather and impacting agriculture. Warmer temperatures can provide more flexibility for crops by increasing the growing season but can also decrease crop yields by accelerating the rate of crop development. During warmer winter and spring seasons, crops are more vulnerable to late season freezes, as plants may be out of their dormant periods when these events occur. For cities, fewer freeze-thaw cycles could decrease road maintenance costs.
Key Findings
Using a regional average of the values shown in the map, we examined the change in the number of days with deeper freeze events, days with minimum temperatures below 20 degrees F, and days with freezing temperatures, days with minimum temperatures below 32 degrees F. We find:
- Under a high emissions scenario, the average annual number of days with minimum temperatures below 20 degrees F in the Mid-Atlantic region are projected to decrease by about 67% by late-century, going from an average of about 43 days/year in the 1991–2020 timeframe to about 14 days/year in the 2081–2099 timeframe.
- Under a high emissions scenario, the average annual number of days per year with minimum temperatures below 32 degrees F in the Mid-Atlantic region is projected to decrease by about 20% by late-century, compared to the baseline period.
Figure 6 allows users to examine how cold low temperatures may be changing in their locations and under different climate scenarios.
Figure 1. Future Projected Average Annual Number of Days with Cold Low Temperatures
How to Use the Tool
Selecting Temperature Thresholds, Time Periods and Future Emissions Scenarios Use the filters to the right of the maps to adjust the temperature threshold and the 30-year time period. Users can also select the future emissions scenario (Low or High Emissions).
Viewing Data for a State or County You can use the State and County filters to the right of the table to have the plot show data for a particular location of interest.
Technical Notes
Localized Constructed Analogs (LOCA) is a downscaled climate data product available at 1/16-degree (6-km) resolution over the continental United States. LOCA data sets1 include the 32 climate models available in the Coupled Model Intercomparison Project 5 (CMIP5) archive, for two future greenhouse gas concentration trajectories: a low emissions future, Representative Concentration Pathway (RCP) 4.5;2 and a high-emissions future, RCP 8.5.3 For this study, we used LOCA data over the Chesapeake Bay watershed from 1991–2100 (or 2099 for some models). Access LOCA datasets and learn more about the methodology.
Data were processed by the Northeast Regional Climate Center to calculate the number of days per year with low temperatures at the given thresholds.
Footnotes
More information on RCP 4.5 can be found in: https://doi.org/10.1007/s10584-011-0151-4 Return to text ⤴
More information on RCP 8.5 can be found in: https://doi.org/10.1007/s10584-011-0149-y Return to text ⤴