Knowing how heat and humidity affect your body can help you stay safe during heat waves Today 06:06 am JST Today | 06:56 am JST By JohnEric W Smith Less than a month into North America’s official summer, heat waves are blistering much of the West. California and the Southwest are facing excessive heat watches for the second time, after a mid-June heat wave pushed temperatures above 100 F (38 C). And in late June an intense heat dome settled over the Pacific Northwest for four days, setting all-time temperature records in Oregon, Washington and British Columbia. The effects were most evident in Lytton, British Columbia, which reported a temperature of 121 F (49.5 C) on June 29, far above its average high for the date of 76 F (24.4 C). A day later, the town was engulfed by a wildfire.