The best time to visit Montreal is during the summer months between March and August. During this time the weather is very pleasant and there are various activities that you can choose from and there are also various festivals like the jazz music festival that take place.
During winter, montreal gets quite cold and unbearable at times. However the feeling of the holiday season is quite enjoyable and there are various festivities that happen during this time. Christmas decorations make the place look very lively and there are various parades and shows that take place in major parts.