Average Weather in Delta Canada
In Delta, the summers are comfortable and partly cloudy and the winters are chilly, wet, and mostly cloudy. Over the course of the year, the temperature typically varies from 34°F to 73°F and is rarely below 23°F or above 80°F.
The warm season lasts for 3.0 months, from June 15 to September 14, with an average daily high temperature above 67°F. The hottest day of the year is August 3, with an average high of 73°F and low of 57°F.
The cool season lasts for 3.4 months, from November 14 to February 26, with an average daily high temperature below 48°F. The coldest day of the year is January 2, with an average low of 34°F and high of 42°F.
Average High and Low Temperature
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
In Delta, 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 Delta begins around June 10 and lasts for 3.7 months, ending around October 2. On August 3, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 72% of the time, and overcast or mostly cloudy 28% of the time.
The cloudier part of the year begins around October 2 and lasts for 8.3 months, ending around June 10. On January 15, the cloudiest day of the year, the sky is overcast or mostly cloudy 73% of the time, and clear, mostly clear, or partly cloudy 27% of the time.
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Delta varies significantly throughout the year.
The wetter season lasts 6.4 months, from October 10 to April 22, with a greater than 35% chance of a given day being a wet day. The chance of a wet day peaks at 59% on November 18.
The drier season lasts 5.6 months, from April 22 to October 10. The smallest chance of a wet day is 10% on August 1.
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 throughout the year is rain alone, with a peak probability of 58% on November 18.
Daily Chance of Precipitation
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. Delta experiences extreme seasonal variation in monthly rainfall.
Rain falls throughout the year in Delta. The most rain falls during the 31 days centered around November 19, with an average total accumulation of 8.9 inches.
The least rain falls around July 31, with an average total accumulation of 0.9 inches.
Average Monthly Rainfall
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. Delta experiences some seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 2.7 months, from November 29 to February 20, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around December 30, with an average total liquid-equivalent accumulation of 0.3 inches.
The snowless period of the year lasts for 9.3 months, from February 20 to November 29. The least snow falls around July 23, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
The length of the day in Delta varies extremely over the course of the year. In 2017, the shortest day is December 21, with 8 hours, 12 minutes of daylight; the longest day is June 21, with 16 hours, 14 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:06 AM on June 16, and the latest sunrise is 3 hours, 0 minutes later at 8:06 AM on December 31. The earliest sunset is at 4:13 PM on December 11, and the latest sunset is 5 hours, 7 minutes later at 9:20 PM on June 25.
Daylight saving time (DST) is observed in Delta 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
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 Delta, 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, remaining a virtually constant 0% throughout.
Humidity Comfort Levels
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 Delta experiences mild seasonal variation over the course of the year.
The windier part of the year lasts for 5.8 months, from October 18 to April 11, with average wind speeds of more than 2.5 miles per hour. The windiest day of the year is December 4, with an average hourly wind speed of 3.5 miles per hour.
The calmer time of year lasts for 6.2 months, from April 11 to October 18. The calmest day of the year is August 9, with an average hourly wind speed of 1.5 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Delta varies throughout the year.
The wind is most often from the south for 6.5 months, from March 22 to October 8, with a peak percentage of 53% on June 21. The wind is most often from the east for 5.5 months, from October 8 to March 22, with a peak percentage of 51% on January 1.
Delta 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 some seasonal variation over the course of the year.
The time of year with warmer water lasts for 3.0 months, from June 16 to September 16, with an average temperature above 57°F. The day of the year with the warmest water is August 2, with an average temperature of 60°F.
The time of year with cooler water lasts for 4.5 months, from November 21 to April 6, with an average temperature below 48°F. The day of the year with the coolest water is January 29, with an average temperature of 45°F.
Average Water Temperature
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 11 to August 21, with an average daily incident shortwave energy per square meter above 5.5 kWh. The brightest day of the year is July 20, with an average of 6.7 kWh.
The darker period of the year lasts for 3.9 months, from October 22 to February 20, with an average daily incident shortwave energy per square meter below 2.0 kWh. The darkest day of the year is December 25, with an average of 0.8 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Delta are 49.144 deg latitude, -122.907 deg longitude, and 190 ft elevation.
The topography within 2 miles of Delta contains only modest variations in elevation, with a maximum elevation change of 367 feet and an average elevation above sea level of 212 feet. Within 10 miles contains only modest variations in elevation (1,211 feet). Within 50 miles contains very significant variations in elevation (8,661 feet).
The area within 2 miles of Delta is covered by artificial surfaces (81%) and shrubs (13%), within 10 miles by artificial surfaces (40%) and cropland (26%), and within 50 miles by trees (44%) and water (32%).
This report illustrates the typical weather in Delta, 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 4 weather stations near enough to contribute to our estimation of the temperature and dew point in Delta.
For each station, the records are corrected for the elevation difference between that station and Delta 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 Delta is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Delta and a given station.
The stations contributing to this reconstruction are: White Rock Automatic Weather Reporting System (29%, 17 kilometers, southeast); P. Meadows Coastal Station Automatic Weather Reporting System (28%, 17 kilometers, east); Vancouver International Airport (22%, 21 kilometers, west); and Vancouver Harbour (21%, 22 kilometers, northwest).
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.