Here's why Portland-area temperatures feel hotter Thursday than previous heat waves

PORTLAND, Ore. (KOIN) -- The summer sizzle is on, but temperatures are feeling hotter than previous heat waves.

Portland has had its fair share of summer heat this year. Afternoon and evening temperatures have already warmed into the 90s and 100 multiple times, but why does Thursday's heat feel so much hotter?

It comes down to the dew point temperature and the heat index.

Thursday afternoon's temperatures warmed into the mid-90s, but it felt closer to 100. That's due to the added moisture in the air. The dew point is the measurement of the available moisture in the atmosphere; Thursday's dew point was relatively high around the Willamette Valley, which means that added moisture makes the air temperature feel even hotter.

Higher humidity values prevent the body from cooling while sweating during the process of evaporative cooling. When humidity values are low, sweat can easily evaporate and cool the body.

Thursday's higher humidity values prevents sweat from evaporating as quickly. So, it makes it feel even hotter than the actual air temperature.