Table 1.

Heat wave definitions used as the basis for the present analysis.

Type	Name	Heat wave criteria	References
NWS, National Weather Service. aThe definitions of heat waves were modified for the present analysis because we used temperature data collected ­during 2001–2004 (from 1 May through 31 September of each year) as the baseline data.
HWD_HI	Heat index–based definition	Days of which the low and the high daily heat index (Hi) are no less than the NWS thresholds of 26.7°C (80°F) and 40.5°C (105°F), respectively.	Robinson 2001
HWD_Tavg	Daily average temperature–based definition	At least 2 consecutive days with daily mean temperature (Tavg) > 95th percentile of Tavg during 2001–2004 in summer.a	Anderson and Bell 2011
HWD_Tmax	Daily maximum temperature–based definition	A heat wave meets three criteria: a) daily maximum temperature (Tmax) > 97.5th percentile of Tmax of summer days during 2001–2004 for at least 3 days, b) the average of Tmax greater than this threshold for the entire period, and c) Tmax > 81.5th percentile of Tmax of summer days during 2001–2004 for every day during the entire period.a	Meehl and Tebaldi 2004; Peng et al. 2011
HWD_Tmin	Daily minimum temperature–based definition	At least 2 consecutive days with daily minimum temperature (Tmin) > 95th percentile of Tmin during 2001–2004 in summer.a	Zhang et al. 2012