With temperatures soaring weeks before summer officially begins, 18 million people across the Northeast and the Northern plains are under heat advisories, and it could be days before relief is on the way. NBC’s Kathy Park reports from Boston and TODAY’s Al Roker forecasts how long the heat will last. » Subscribe to TODAY: http://on.today.com/SubscribeToTODAY » Watch the latest from TODAY: http://bit.ly/LatestTODAY About: TODAY brings you the latest headlines and expert tips on money, health and parenting. We wake up every morning to give you and your family all you need to start your day. If it matters to you, it matters to us. We are in the people business. Subscribe to our channel for exclusive TODAY archival footage & our original web series. Connect with TODAY Online! Visit TODAY's Website: http://on.today.com/ReadTODAY Find TODAY on Facebook: http://on.today.com/LikeTODAY Follow TODAY on Twitter: http://on.today.com/FollowTODAY Follow TODAY on Instagram: http://on.today.com/InstaTODAY