Photograph by Stephen Downes on Flickr
Many people think that Moncton’s climate is maritime-like, similar to most cities located in the Maritime Provinces of Canada. After all, it is close to the Bay of Fundy and the Northumberland Strait. However, the city’s weather tends to be continental during most of the year.
Climatologists consider Moncton to have a “warm summer continental” or “Hemiboreal” climate with uniform precipitation distribution. The city enjoys almost 2,000 hours of sunshine each year (40% of daylight hours), and just over 1,000 cm of precipitation.
Moncton summer tend to be pleasantly warm—perfect weather for lounging on the patio deck. Daytime highs average around 25 °C (77 °F) but can exceed 30 °C (86 °F) a few days each year. The higher (and more humid) temperatures are the result of seasonal prevailing westerly winds that strengthen the continental tendencies of the summer climate. Rainfall is generally modest, especially in late July and August.
Autumn is the season that Moncton most resembles it’s maritime neighbors. This is influenced by the retention of heat in the nearby Gulf of St. Lawrence. As a result, daytime temperatures remain mild until mid October. The first snowfalls do not usually occur until mid November. However, any delay in snowfall is more than made up for by the seasonal storms that hit the city in late fall. The stormiest weather of the year occur during the transition to winter between mid-December and mid-January.
Winter days in Moncton are cold—but they’re usually sunny! Daytime temperatures hover just below the freezing point. However there are several cold snaps each winter when temperatures fall to -25 °C (-13 °F) or colder. Balancing these are a handful of “January thaws” each year when considerable snow melt can occur. Major snowfalls can result from nor’easters—ocean storms moving up the coast following the jet stream from the southeastern United States. These storms can result in heavy precipitation, often amplified by “sea effect” snow squall activity.
Spring traditionally comes late to Moncton. This is because the sea ice that forms in the Gulf of St. Lawrence during the winter takes time to melt, cooling the prevailing onshore winds. Over the course of the last decade, however, the ice burden in the Gulf has diminished considerably. As a result, the springtime cooling effect has significantly weakened. Daytime temperatures above freezing are typical by mid March. Trees are usually in full leaf by the end of May.
And remember, if you don’t like the weather here, just wait a minute…it’ll change.