Some Mainers might have noticed a milky appearance to the sky Sunday.

Smoke from wildfires in Canada and parts of the United States seems responsible for drowning out what otherwise would have been a mostly sunny day.

The veil of smoke was visible on satellite imagery during the day.

The National Weather Service in Caribou says the smoke was fairly dense aloft, covering the Crown of Maine during the morning.

As the day progressed, the smoke spread farther south and west.

By sunset at Sebec Lake in Dover-Foxcroft, the smoke aloft added a bit of a muted color to the sky.

This does occur from time to time, when smoke particles from large wildfires rise high into the atmosphere, and are then carried by upper-level winds overhead.

Other parts of the northeast were affected by wildfire smoke as well. On Saturday, it was particularly dense in upstate New York.

The smoke is far enough aloft that in Maine, it is not impacting air quality at the surface.

With a similar flow in place Monday, the smoke might still be overhead.