The National Weather Service anticipates a low of -3 degrees tonight and another plunge, to -9 degrees, on Monday night. Tuesday's daytime temperature is expected to hover around 4 degrees.

These are perfect times to stay snug and warm indoors. But for those who must venture outside, here are some tips from the Pennsylvania Department of Health:

Adults and children should wear hats, scarves or knit masks to cover the face and mouth, sleeves that are snug at the wrist, mittens (they are warmer than gloves), water-resistant coat and boots, and several layers of loose-fitting clothing.

Outer clothing should be tightly woven to prevent loss of body heat.

The American Red Cross advises people to stay dry: wet clothing chills the body quickly. Excess sweating will also accelerate heat loss, so remove extra layers of clothing if you feel too warm.

Shivering is the first sign that your body is losing heat, and is a sign that it's time to come back indoors.

The elderly and the very young, and those who have chronic illnesses such as heart disease or breathing problems, need to stay indoors. Be sure to check on elderly family members, friends and neighbors. They may need help shoveling sidewalks, making sure their heating systems are functioning properly, or having medications refilled or grocery shopping.

Seek medical attention immediately if you have symptoms of hypothermia, including: confusion, dizziness, exhaustion and severe shivering. Watch for symptoms of frostbite, including numbness, flushed gray, white, blue or yellow skin discoloration, numbness, or waxy feeling skin.