The climate of Lombardy varies considerably depending on where you are – it’s considerably colder in the mountains, for example, than it is in the low-lying plains areas.

Overall, however, the region enjoys a classic continental climate – warm to hot in summer, cool to cold in the winter, with lovely seasons bookending them – fall is colorful and cool, while spring is (also) colorful and relatively warm.

The most popular time to visit is in the summer, and you can generally enjoy temperatures in the 70s and 80s during the summer months. But this is also when you’ll find large numbers of fellow travelers. If you want to enjoy Lombardy without plenty of other tourists to commiserate with, head here in the fall and winter, when crowds are less and room rates will possibly be cheaper.

Although it can rain anytime of the year, especially in the mountain regions of Lombardy, you’ll find it fairly dry in the flatlands most parts of the year.  Winter months can bring with them heavy, dense fog, which will often burn off by mid-morning, however.  If in the mountains, be prepared for rain anytime, and heavy snowfall in winter months.

One source of information on weather and climate in the region is the website of the regional government's environment protection agency: http://ita.arpalombardia.it/meteo/met...

Others include:

http://www.accuweather.com/en/it/25/l...

http://www.weather.com/weather/tenday...