Bologna has a continental climate, without any influence from the seaside; the Climatic Classification is "zone E, 2259 GR/G". Winters can be cold (−28.8 °C (−20 °F) was recorded in Molinella on the night of January 12, 1985).
The record lows recorded in the last twenty years are around −10 °C (14 °F), while summers are hot and muggy due to the high humidity in this area, and they can be long with long periods of drought (as in 2003); in July and August it is normal for temperatures to rise above 37 °C (99 °F).
Annual precipitation oscillates between around 450 mm and 900 mm, with the majority generally falling in spring and autumn.
Moderate wind contributes to the formation of fog and haze and to an elevated smog due to local traffic, as well as to the combustion in heating systems (most of which have been converted to methane gas) and industrial establishments. Occasionally, despite all of this, there have been days with gusts up to 120 km/hour (for example on December 26, 1996) due to the winds coming down off the mountains (sometimes the buran from the Siberian steppe reaches the foot of the Apennines); during the month of August, in particular, strong gusts of more than 100 km/hour have been recorded during localized
