If you are planning to visit Monaco for a dream luxurious holiday, you can visit it anytime of the year, as the excellent Mediterranean weather prevails almost throughout the year and anytime is considered to be a good time for visiting Monaco. However, summer is the peak tourist time- between June to August. Prices and crowds are both high around the time.
To experience winter at Monaco, you need to visit during December to February. Christmas is celebrated with much gusto at Monte Carlo and other cities.