The National Weather Service Phoenix released data Tuesday that showed heat is coming to the Valley earlier than it used to and it's sticking around longer.

The graphs, released in a tweet, tracks the first and last day Phoenix experiences temperatures ranging from 85 to 110.

On average, the Valley's first day of 110 degrees is coming 16 days earlier than it did a century ago, and the last day is coming 31 days later, according to the charts.

NWS said they analyzed data going back to 1896 to track the trends. The twelve decades of data is "more than enough to show trends," NWS explained.

Phoenix continues to get warmer, in part, because of the urban heat island effect, according to 12 News meteorologist James Quinones.

The concrete, steel and glass that make up the city retain our daytime heat in the overnight hours, so the city doesn't cool off as much as it used to. This effect has a greater impact on lows than it does on highs.

(Photo: 12 News)