Climate and Energy Action Plan (CEAP)

CLIMATE TRENDS & PRO JECTIONS | CITY OF ASHLAND, OREGON | FINAL REPORT | 16 Extreme Cold Temperature Extreme cold temperature pr ojections are examined using t wo standard metrics: 1) the coldest night of the year , and 2) number of frost days per year . Coldest Night of Year The range of future changes in th e temperature of the coldest night of the year in Ashland is 1°F to 8°F for the 2050s and 0 °F to 11 °F for the 2080s compared to the historical period (see Table 2); this is the range across all models and both emissions scenarios. The multi -model mean projects an increase of about 8 °F by the 2080s under the high emissions scenario compared to the historic baseline (1950 -2005) (see Figure 4). Projected increases in the coldest night of the year are smaller than projected increases in the hottest day of the year. Figure 8. Temperature of the coldest night of year projections for Ashland as simulated by 18 downscale d global climate models for the historical period (1950 -2005) and future (2006 -2099) under a low (RCP4.5) and high (RCP8.5) greenhouse gas emissions scenario. Solid line and shading depicts the 18 -model mean and range, respectively. The multi -model mean di fferences for the 2050s (2040 -2069 average) and 2080s (2070 -2099 average) compared to the historical baseline (1950 -2005) are displayed. Frost Days A frost day is counted when the minimum temperature drops below 32°F. Projections indicate the number of frost days per year in Ashland is likely to decrease by between 19 to 68 days by the 2050s and 25 to 99 days by the 2080s (refer back to Table 2); this is the range of future changes across all models and both emissions scenarios. The multi -model mean projects 80 fewer frost days by the 2080s under the high emissions scenario compared to the historic baseline (1950 -2005) (see Figure 5). Ashland Coldest Night of Y ear Pr ojections°F Histor ical Low (RCP4.5) High (RCP8.5) 2050s +3 °F2050s +5 °F 2080s +4 °F2080s +8 °F −30−25−20−15−10−505101520253035 1950 1970 1990 2010 2030 2050 2070 2090