Although it is located in the northern part of the Adriatic near Slovenia, Trieste has a fairly mild Mediterranean climate.  During the winter months (December through February) the city's temperatures average in the 40's, rarely if ever dropping below the freezing mark.  The late fall and winter is also when the area gets most of its yearly precipitation, with the average rainfall being about three inches per month from October to January.  Trieste's summers are warm to moderately hot and relatively dry compared to its winters.  The average summer temperature in Trieste (July and August) is in the low to mid 80's. 

The most remarkable factor in Trieste's weather is the wind.  The city has an Italy-wide reputation as 'windy city' -- pretty much like Chicago in the US -- because of the 'bora', a ferocious wind which blows from East/NorthEast.  It does not blow always, mind you, but when it does its gusts can reach 150 kph.

Most visitors choose to come to Trieste during the warmer spring and summer months in order to best enjoy the area's many beaches and other seaside activities such as boating and windsurfing. 

For an up to date weather forecast on Trieste, complete with maps and averages, visit MSN's Trieste weather page.