Saint John (NB) Temperature by Month

Saint John in New Brunswick, Canada sees significant seasonal temperature differences, with daytime highs between -1°C (30°F) in January and 21°C (70°F) in August, averaging 10°C (50°F) annually. Explore the full monthly breakdown below.

The climate in Saint John is known for significant temperature differences throughout the year. At night, this contrast is just as clear, with lows ranging from 14°C (57°F) in August to -10°C (14°F) in January.

The chart below illustrates the average maximum day and minimum night temperatures in Saint John by month:

Low temperatures are most often recorded between 4 AM and 6 AM, while highs typically occur around 3 PM.

The chart below shows the average temperature throughout the year:

Saint John's average annual maximum temperature is 10°C (50°F). To put that in context, here's how it compares to a few well-known destinations:

Rome, Italy averages 20°C (68°F) annually, with reliably warm summers and comfortable winters.

Glasgow, Scotland averages 13°C (55°F) a year, mild but often grey, with cold winters and rarely hot summers.

Seoul, South Korea averages 18°C (64°F) a year, with four clear seasons, cold winters, and hot humid summers.

Perth, Australia averages 25°C (77°F) annually, with a classic Mediterranean climate, hot dry summers and mild wet winters.

Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.

The readings come from a range of sources, land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.

Global average temperatures have risen by around 1.2°C since the pre-industrial era, and the effects are visible across many regions. Winters are milder on average, with fewer frost days and less snow in many parts of the world. Heatwaves are more frequent and more intense, and Europe's summers of 2018, 2019, and 2020 all set records.

Summers are also getting drier in some areas, while winter rainfall has increased in others. This contributies to higher river levels and more flooding. In many countries, spring arrives earlier and autumn lasts longer. It has knock-on effects for wildlife, agriculture, and local ecosystems.

For more on Saint John's weather, including monthly rainfall, sunshine hours, and humidity, visit our Saint John climate page.