If i take my infant daughter 4 a hike during winter(canada), how to make sure she isn't too cold/hot?

Thermometer/Ask: A 4 yo should be able to tell you how she feels. A readily available infrared eardrum thermometer, temporal artery thermometer or old fassion oral thermometer should give you more data. Kids sweat a lot into the back of their hair if hot & shiver when cold. With proper warm clothing this should be a great outing. (between 97.5 - 99.5f would be my comfort zone).

Hypthermia: Hypothermia develops when a child's temperature falls below normal due to exposure to colder temperatures. It often happens when a youngster is playing outdoors in extremely cold weather without wearing proper clothing or when clothes get wet. It can occur more quickly in children than in adults. Aap recommends several thin layers will keep them dry and warm. Don’t forget warm boots, gl.