Pete Sack

While the Chicago area has grown used to cooler weather in recent days, that's about to change, with dangerous heat on the way as temperatures climb into the 90s and heat index values top 100 degrees. With the hottest weather of the year so far expected, NBC 5 Storm Team Meteorologist Pete Sack said it'll be time to fire up the air conditioning, likely beginning Sunday and then continuing for much of the week.

Sunshine and comfortable temperatures are in store for Saturday - and, to our delight, those conditions will likely persist throughout the day, so it'll be a great chance to get outside while you can. Unfortunately, Father's Day is not looking as promising weather-wise. Saturday, though, began with blue skies and sunshine over O'Hare Airport and not a cloud on the horizon.