It used to be that people didn’t need an air conditioning unit if they lived in cities by the San Francisco Bay, such as Berkeley, Oakland or San Francisco. But thanks in part to something called the urban heat island effect, summertime in most Bay Area cities is getting more and more unbearable each year. Melissa Colorado reports.

Stay connected:
Follow us on Twitter: http://www.twitter.com/nbcbayarea
Like us on Facebook: http://www.facebook.com/nbcbayarea
Follow us on Instagram: http://www.instagram.com/nbcbayarea
Add us on Snapchat @NBCBayArea

Catch up on all the day’s news: http://www.nbcbayarea.com

Download our app:
On iOS: http://nbcbay.com/R1BhqYM
On Android: http://nbcbay.com/rUcA97h