After a brief break from temperatures usually reserved for late July, the final day of spring and first day of summer will bring the heat. According to the National Weather Service, daytime highs will climb into the mid-90s with higher-than-normal humidity for the season, and heat index values will approach and possibly top 100. Those who need to be outdoors should stay hydrated and take plenty of breaks in shade and air conditionings. Chances for scattered thunderstorms remain in the forecast for most of the evenings and overnights this week as well.