Hamilton's climate is humid-continental, characterized by changeable weather patterns. However, its climate is moderate compared with most of Canada. Hamilton's location on an embayment at the south-western corner of Lake Ontario with an escarpment dividing upper and lower parts of the city results in noticeable disparities in weather over short distances, this is also the case with pollution levels, which depending on localized winds patterns or low clouds can be high in certain areas mostly originating from the city's steel industry mixed with regional vehicle pollution. With a July average of exactly 22.0 °C (71.6 °F), the lower city is located in a pocket of the Dfa climate zone found at the south-western end of Lake Ontario (between Hamilton and Toronto and eastward into the Niagara Peninsula), while the upper reaches of the city fall into the Dab climate zone.
The airport's open, rural location and higher altitude (240m vs. 85m ASL downtown) results in lower temperatures, generally windier conditions and higher snowfall amounts than lower, built-up areas of the city. One exception is on early spring afternoons, when colder than air lake temperatures keep shoreline areas significantly cooler, under the presence of an east or north-east onshore flow
