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Average Weather in St. John's Canada

In St. John's, the summers are short and comfortable; the winters are long, freezing, and windy; and it is partly cloudy year round. Over the course of the year, the temperature typically varies from 19°F to 69°F and is rarely below 8°F or above 78°F.

Temperature

The warm season lasts for 2.9 months, from June 23 to September 18, with an average daily high temperature above 62°F. The hottest day of the year is August 2, with an average high of 69°F and low of 56°F.

The cold season lasts for 3.9 months, from December 6 to April 2, with an average daily high temperature below 38°F. The coldest day of the year is January 31, with an average low of 19°F and high of 31°F.

Average High and Low Temperature

The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Average Hourly Temperature

Average Hourly Temperature in St. John'sJanFebMarAprMayJunJulAugSepOctNovDec12 AM4 AM8 AM12 PM4 PM8 PM12 AMcoolcoldfreezingvery coldcomfortable
The average hourly temperature, color coded into bands: frigid < 15°F < freezing < 32°F < very cold < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The shaded overlays indicate night and civil twilight.

Clouds

In St. John's, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year in St. John's begins around June 28 and lasts for 5.5 months, ending around December 10. On September 15, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 51% of the time, and overcast or mostly cloudy 49% of the time.

The cloudier part of the year begins around December 10 and lasts for 6.6 months, ending around June 28. On May 9, the cloudiest day of the year, the sky is overcast or mostly cloudy 70% of the time, and clear, mostly clear, or partly cloudy 30% of the time.

Cloud Cover Categories

Cloud Cover Categories in St. John'sclearercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Sep 1551%Sep 1551%May 930%May 930%Jun 2840%Jun 2840%Dec 1041%Dec 1041%partly cloudymostly cloudyclearovercastmostly clear
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds: clear < 20% < mostly clear < 40% < partly cloudy < 60% < mostly cloudy < 80% < overcast.

Precipitation

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in St. John's varies throughout the year.

The wetter season lasts 5.8 months, from September 20 to March 13, with a greater than 36% chance of a given day being a wet day. The chance of a wet day peaks at 42% on November 22.

The drier season lasts 6.2 months, from March 13 to September 20. The smallest chance of a wet day is 30% on August 13.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation in St. John's changes throughout the year.

Rain alone is the most common for 9.5 months, from March 23 to January 7. The highest chance of a day with rain alone is 39% on November 2.

Mixed snow and rain is the most common for 1.5 months, from January 7 to January 20 and from February 19 to March 23. The highest chance of a day with mixed snow and rain is 16% on February 28.

Snow alone is the most common for 4.3 weeks, from January 20 to February 19. The highest chance of a day with snow alone is 17% on February 1.

Daily Chance of Precipitation

The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. St. John's experiences significant seasonal variation in monthly rainfall.

Rain falls throughout the year in St. John's. The most rain falls during the 31 days centered around October 16, with an average total accumulation of 4.2 inches.

The least rain falls around February 8, with an average total accumulation of 1.6 inches.

Average Monthly Rainfall

Average Monthly Rainfall in St. John'sJanFebMarAprMayJunJulAugSepOctNovDec0 in1 in2 in3 in4 in5 in6 in7 inOct 164.2 inOct 164.2 inFeb 81.6 inFeb 81.6 inJul 52.8 inJul 52.8 in
The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average liquid-equivalent snowfall.

Snowfall

We report snowfall in liquid-equivalent terms. The actual depth of new snowfall is typically between 5 and 10 times the liquid-equivalent amount, assuming the ground is frozen. Colder, drier snow tends to be on the higher end of that range and warmer, wetter snow on the lower end.

As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. St. John's experiences significant seasonal variation in monthly liquid-equivalent snowfall.

The snowy period of the year lasts for 6.4 months, from November 5 to May 17, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around February 2, with an average total liquid-equivalent accumulation of 2.0 inches.

The snowless period of the year lasts for 5.6 months, from May 17 to November 5. The least snow falls around August 8, with an average total liquid-equivalent accumulation of 0.0 inches.

Average Liquid-Equivalent Monthly Snowfall

Average Liquid-Equivalent Monthly Snowfall in St. John'ssnowsnowJanFebMarAprMayJunJulAugSepOctNovDec0 in1 in2 in3 in4 inFeb 22.0 inFeb 22.0 inAug 80.0 inAug 80.0 inNov 50.1 inNov 50.1 inMay 170.1 inMay 170.1 in
The average liquid-equivalent snowfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average rainfall.

Sun

The length of the day in St. John's varies significantly over the course of the year. In 2017, the shortest day is December 21, with 8 hours, 26 minutes of daylight; the longest day is June 21, with 15 hours, 59 minutes of daylight.

Hours of Daylight and Twilight

Hours of Daylight and Twilight in St. John'sJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 7 minMar 2012 hr, 7 minMar 2015 hr, 59 minJun 2115 hr, 59 minJun 2112 hr, 10 minSep 2212 hr, 10 minSep 228 hr, 26 minDec 218 hr, 26 minDec 21nightnightday
The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise is at 5:02 AM on June 16, and the latest sunrise is 2 hours, 47 minutes later at 7:49 AM on November 4. The earliest sunset is at 4:09 PM on December 11, and the latest sunset is 4 hours, 53 minutes later at 9:02 PM on June 25.

Daylight saving time (DST) is observed in St. John's during 2017, starting in the spring on March 12, lasting 7.8 months, and ending in the fall on November 5.

Sunrise & Sunset with Twilight and Daylight Saving Time

Sunrise & Sunset with Twilight and Daylight Saving Time in St. John'sJanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 165:02 AMJun 165:02 AM9:02 PMJun 259:02 PMJun 25Dec 114:09 PMDec 114:09 PM7:49 AMNov 47:49 AMNov 4Mar 12DSTMar 12DSTDSTNov 5DSTNov 5daynightnightnightnightSolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day over the course of the year 2017. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray. The transitions to and from daylight saving time are indicated by the 'DST' labels.

Humidity

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

The perceived humidity level in St. John's, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, staying within 3% of 3% throughout.

Humidity Comfort Levels

Humidity Comfort Levels in St. John'sJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Dec 60%Dec 60%Aug 86%Aug 86%drydrycomfortablecomfortablehumidhumid
The percentage of time spent at various humidity comfort levels, categorized by dew point: dry < 55°F < comfortable < 60°F < humid < 65°F < muggy < 70°F < oppressive < 75°F < miserable.

Wind

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in St. John's experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 5.9 months, from October 13 to April 10, with average wind speeds of more than 13.1 miles per hour. The windiest day of the year is January 14, with an average hourly wind speed of 16.3 miles per hour.

The calmer time of year lasts for 6.1 months, from April 10 to October 13. The calmest day of the year is August 2, with an average hourly wind speed of 9.8 miles per hour.

Average Wind Speed

The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The predominant average hourly wind direction in St. John's varies throughout the year.

The wind is most often from the south for 4.7 months, from April 8 to August 29, with a peak percentage of 43% on July 15. The wind is most often from the west for 7.3 months, from August 29 to April 8, with a peak percentage of 51% on January 1.

Wind Direction

Wind Direction in St. John'sWSWJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%northwestsoutheast
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions (north, east, south, and west), excluding hours in which the mean wind speed is less than 1 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Water Temperature

St. John's is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.

The average water temperature experiences significant seasonal variation over the course of the year.

The time of year with warmer water lasts for 2.4 months, from July 18 to September 29, with an average temperature above 52°F. The day of the year with the warmest water is August 20, with an average temperature of 57°F.

The time of year with cooler water lasts for 5.0 months, from December 14 to May 16, with an average temperature below 37°F. The day of the year with the coolest water is March 5, with an average temperature of 31°F.

Average Water Temperature

The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

Solar Energy

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy experiences extreme seasonal variation over the course of the year.

The brighter period of the year lasts for 3.3 months, from May 13 to August 22, with an average daily incident shortwave energy per square meter above 5.1 kWh. The brightest day of the year is July 11, with an average of 6.1 kWh.

The darker period of the year lasts for 3.7 months, from October 30 to February 18, with an average daily incident shortwave energy per square meter below 2.0 kWh. The darkest day of the year is December 21, with an average of 0.9 kWh.

Average Daily Incident Shortwave Solar Energy

The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

For the purposes of this report, the geographical coordinates of St. John's are 47.565 deg latitude, -52.709 deg longitude, and 243 ft elevation.

The topography within 2 miles of St. John's contains significant variations in elevation, with a maximum elevation change of 741 feet and an average elevation above sea level of 214 feet. Within 10 miles contains significant variations in elevation (846 feet). Within 50 miles also contains very significant variations in elevation (1,093 feet).

The area within 2 miles of St. John's is covered by sparse vegetation (34%), artificial surfaces (33%), trees (20%), and water (11%), within 10 miles by water (44%) and trees (34%), and within 50 miles by water (72%) and trees (16%).

Data Sources

This report illustrates the typical weather in St. John's, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.

Temperature and Dew Point

There are 2 weather stations near enough to contribute to our estimation of the temperature and dew point in St. John's.

For each station, the records are corrected for the elevation difference between that station and St. John's according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.

The estimated value at St. John's is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between St. John's and a given station.

The stations contributing to this reconstruction are: St. John's International Airport (97%, 7 kilometers, northwest) and Cape Race, Nfld (2.6%, 105 kilometers, south).

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , by Jean Meeus.

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for aiports and weather stations are provided by AskGeo.com .

Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.

Disclaimer

The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.