The National Oceanic Atmospheric Association is reporting a Dense Fog Advisory through 8:00 this morning for Ingham and surrounding counties, as well as Southwestern Michigan. Visibility is expected to be less than a quarter mile in some areas with the fog settling over the region.

Makes sense that it's foggy this morning, given that temps were in the upper 50s yesterday, then it seemed to warm up over night.
Sure, we all know what fog is, but here's what Wikipedia says about how it forms:

Fog begins to form when water vapor condenses into tiny liquid water droplets suspended in the air. Six examples of ways that water vapor is added to the air are by wind convergence into areas of upward motion;[6] precipitation or virga falling from above;[7] daytime heating evaporating water from the surface of oceans, water bodies, or wet land;[8]transpiration from plants;[9] cool or dry air moving over warmer water;[10] and lifting air over mountains.[11] Water vapor normally begins to condense on condensation nuclei such as dust, ice, and salt in order to form clouds.[12][13] Fog, like its elevated cousin stratus, is a stable cloud deck which tends to form when a cool, stable air mass is trapped underneath a warm air mass.[14]

Fog normally occurs at a relative humidity near 100%.[15] This occurs from either added moisture in the air, or falling ambient air temperature.[15] However, fog can form at lower humidities, and can sometimes fail to form with relative humidity at 100%. At 100% relative humidity, the air cannot hold additional moisture, thus, the air will become supersaturated if additional moisture is added.

We might see peeks of the sun once the fog clears and there's still a chance of some rain or a thunderstorm later today with temperatures headed to about 80 degrees!
NOAA does advise to go a bit slower in the fog, use your low beams and leave some space between you and the vehicle in front of you.