HUNTSVILLE, Ala. - If you spent any time outside Sunday, you've felt a noticeable change in our air. Fall arrives in just over a week, so expect this cool feel to become more common very soon.
If you have an early morning and late afternoon commute, you may have noticed something else - a seemingly brighter sun.
There hasn't been any change in the brightness of the sun, but the glare is noticeably more pronounced - and it can really impact drivers.
Regardless of where you are on the globe, the sun rises exactly in the east and sets exactly in the west on two days of the year: March 21 and September 21. Those dates correspond to the Vernal and Autumnal (spring and fall) equinoxes.
Days like today where it was cooler and drier make the sun's glare even worse. Cooler temperatures mean lower humidity which in turns means less haze. We did a story in the summer of 2014 about what factors impact haze and the two most prominent are temperature and humidity.
We found that the lower the temperature, the less haze is likely to form (this is why we describe most summer days as hot and hazy). The lower the humidity, the less concentrated the haze particles will be. On summer days, haze appears thicker on the horizon in the morning due to high humidity.
While haze gives the sky a "dirty" appearance, it acts to scatter the sun's light rays-- making it less bright or direct to our eyes. With no haze, we've gotten nearly-unobstructed sunlight the past few days.
Generally east-west oriented roads (I-565, Highway 72, Highway 20, Highway 278) will be the most affected. These also happen to be some of the most heavily-traveled roads in the Tennessee Valley.
There are some other factors that can make visibility even worse-- the main one being a dirty windshield.
There is an equal risk of accidents both in the morning and the evening. If you're traveling into the sun (i.e. from Madison to Huntsville in the morning), of course your sight is reduced ahead of you. But even if you're traveling west in the morning and not directly into the sun, having the sun behind you is still affecting drivers headed east.