To be frank, it really depends on environment also. Like these days i am in Australia and env. is so good for walking that you feel like going for it. Streets are clean. Whether is good. No dust. In India its really hard for you to walk to office even if you are in proximity.. Best time is to go early morning walk around 5-6 but we can hardly do that.. :( :(

Walking is the most useful exercise especially, in the morning. It is a light exercise. "Half an hour morning walk keeps the doctor away". The atmosphere is clear and pure. The air is fresh. Deep breathing and brisk walk in the open air atmosphere gives freshness to mind and energy to lungs. It improves the physical health. A man on his early morning walk enjoys the beauty of nature smelling the sweet scented aid of flowers blooming everywhere. The sound of leaves of the trees is a sort of sweet music. When the sun rises, its light and soft rays appear to be charming to the mind and body.

Advantages:-
Morning walk has its own advantages. Morning walk helps in improving the blood circulation and physical strength of a person. If done for forty to forty five minutes, helps in burning calories thereby losing weight. It keeps one active and energetic and takes away dullness from one's life. It tones up the whole system and develops stamina for performing tasks which need physical strength and prepares the person for the days work. It vitalizes our systems such as, circulatory system, respiratory system, excretory system, etc. One of the greatest merits of morning walk is that it refreshes not only our body but also soothes our burdened minds and tensioned hearts. A good morning walk can do wonders with regard to mental health.

Do's for walking:-
One should be very careful about the place where one takes walk.
Preferably, it should be an open place with plenty of fresh and clean air.
Wear comfortable shoes and loose clothing.

Don'ts for walking:-
Busy roads,congested residential areas,dirty streets, etc., should be avoided.
Avoid taking caffeinated beverages immediately before going on walk.

Though it is cold, you have to do morning walk at least in your house as walking is good for health