Number of days per year with a daily maximum wet-bulb temperature exceeding 32°C (90°F) at the ”potential” climate warming scenario of +2.0°C. On the current path of emissions, in the 2040s the average surface temperature will likely pass 2.0°C above the pre-industrial 1850-1900 average (a standard baseline time period in climate science). Wet-bulb temperature is calculated using temperature and humidity. High wet-bulb temperatures can impair the human body’s ability to self-cool through sweating. 32°C or 90°F wet-bulb can occur at 32°C (90°F) air temperature and 99% relative humidity, or 40°C (104°F) and 55% humidity.For each warming scenario, the number of days exceeding 32°C (90°F) wet-bulb are identified from daily maximum wet-bulb temperatures computed using daily maximum temperature and daily minimum relative humidity, variables that are projected by climate models. The displayed values are from a range of simulated years from multiple models. Actual outcomes may prove to be higher or lower than the displayed values.