There is a dense fog advisory in effect until midnight Monday, according to the National Weather Service.
Pockets of heavy fog are already blanketing Long Island, including Port Washington.
With visibility one-quarter mile or less, drivers and pedestrians alike should take caution.
When driving, be sure to increase the car distance between you and the car in front of you. AAA advises slowing down and turning on your low-beam headlights to increase your visibility to other drivers.
Use turn signals well in advance so other drivers know of your intentions, and be sure to brake early and gradually to give drivers behind you time to react, the New York’s Department of Motor Vehicles says.
Pedestrians should be aware that it may be harder for drivers to see them, so cross only in designated crosswalks, and be sure that drivers can see you.