Climate averages 1991–2020
Saint John weather
in December.
A cold month with heavy precipitation: the 10th warmest and the wettest of the year.
Long-term climate patterns, not a forecast for a particular trip.
December is a cold month in Saint John: daytime highs average 1.2°C and nights cool to about -5.3°C. By daytime temperature it is the 10th warmest of the 12 months.
Expect about 137 mm of precipitation on roughly 13 days, which makes December a month with heavy precipitation (the wettest month of the year). Daylight, from sunrise to sunset, lasts about 8 h 49 min on an average December day.
The nearest other city in this atlas is Moncton (134 km away). In December its highs average -0.1°C, 1.3°C cooler than Saint John, with 112 mm of precipitation.
Among the 86 cities listed in Canada, Saint John ranks joint 38th of 86 for the warmest December highs and 72nd of 86 for the driest December (precipitation, lowest first). The mean December high of those 86 cities is 0.2°C; Saint John is 1.0°C warmer than that mean.
From December to January, average highs fall by 3.8°C to -2.6°C, and monthly precipitation falls from 137 mm to 112 mm.
The annual picture
December in context
Monthly precipitation
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Saint John climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | -2.6°C-10.2°C | -10.2°C | 112 | 11.6 | 9.29 h |
| February | -1.7°C-9.1°C | -9.1°C | 96 | 10.3 | 10.410 h |
| March | 1.9°C-4.9°C | -4.9°C | 112 | 11.4 | 11.912 h |
| April | 7.4°C0.7°C | 0.7°C | 105 | 12.3 | 13.513 h |
| May | 13.4°C6.1°C | 6.1°C | 104 | 12.3 | 14.815 h |
| June | 17.8°C11.0°C | 11.0°C | 108 | 12.1 | 15.616 h |
| July | 20.8°C14.6°C | 14.6°C | 91 | 11.0 | 15.315 h |
| August | 21.0°C14.9°C | 14.9°C | 80 | 9.3 | 14.114 h |
| September | 17.8°C11.8°C | 11.8°C | 108 | 10.0 | 12.613 h |
| October | 12.3°C6.6°C | 6.6°C | 133 | 10.9 | 11.011 h |
| November | 6.7°C1.0°C | 1.0°C | 128 | 11.8 | 9.610 h |
| December, selected | 1.2°C-5.3°C | -5.3°C | 137 | 13.1 | 8.89 h |
Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
December in nearby cities
- Moncton in DecemberCanada · 134 kmHigh -0.1°C · Low -7.5°C · 112 mm precipitation
- Dartmouth in DecemberCanada · 206 kmHigh 2.9°C · Low -3.0°C · 134 mm rain
- Halifax in DecemberCanada · 207 kmHigh 3.0°C · Low -2.5°C · 134 mm rain
- Québec in DecemberCanada · 433 kmHigh -3.2°C · Low -11.1°C · 101 mm precipitation
- Sherbrooke in DecemberCanada · 457 kmHigh -1.3°C · Low -9.4°C · 92 mm precipitation
- Sydney, Canada in DecemberCanada · 466 kmHigh 2.6°C · Low -2.1°C · 139 mm rain
- Lawrence (Massachusetts), United States in DecemberUnited States · 498 kmHigh 3.9°C · Low -3.4°C · 104 mm rain
- Manchester, United States in DecemberUnited States · 499 kmHigh 2.8°C · Low -4.8°C · 104 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Saint John) is explained once on the Saint John year overview and on the Sources, method and limits page.