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Average Weather on January 21 in Delta Canada

On January 21, the temperature in Delta typically ranges from 35°F to 43°F and is rarely below 25°F or above 50°F.

For reference, on July 31, the hottest day of the year, temperatures in Delta typically range from 54°F to 75°F, while on January 2, the coldest day of the year, they range from 32°F to 42°F.

The coolest time of the day is from 9:00 PM to 9:15 AM, with the coldest at 6:45 AM, at which time the temperature is below 41°F three days out of four, and below 44°F nine days out of ten.

The warmest time of the day is from 12:00 PM to 4:30 PM, with the hottest at 2:45 PM, at which time the temperature is above 40°F three days out of four, and above 34°F nine days out of ten.

The day has gained half its heat by 10:30 AM and lost it again by 5:30 PM.

Average Temperature on January 21

Average Temperature on January 21 in Deltanightdaynight12 AM3 AM6 AM9 AM12 PM3 PM6 PM9 PM12 AM25°F30°F35°F40°F45°F50°F2:45 PM43°F2:45 PM43°F35°F6:45 AM35°F6:45 AM37°F9:00 PM37°F9:00 PM37°F9:15 AM37°F9:15 AM12:00 PM41°F12:00 PM41°F4:30 PM41°F4:30 PM41°FNowNow
The hourly average temperature (purple line), with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the hourly average perceived temperature. Civil twilight and night are indicated by shaded overlays.

The figure below shows you a compact characterization of the range of temperatures experienced on January 21 throughout the historical record. The horizontal axis is the time of day and the colored stacked areas indicate the percentage of hours spent in various temperature bands.

Temperature Bands on January 21

Temperature Bands on January 21 in Deltanightdaynight12 AM3 AM6 AM9 AM12 PM3 PM6 PM9 PM12 AM0%100%20%80%40%60%60%40%80%20%100%0%NowNowfreezingvery coldcold
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 percentage of time spent in various temperature bands. Civil twilight and night are indicated by shaded overlays.

Laboissière-en-Thelle, France (4,900 miles away) is the far-away foreign place with temperatures most similar to Delta (view comparison).

Compared to January 21 (excluding 30 days before and after), December 5 has the most similar daily average high and low temperatures.

Clouds

The average percentage of the sky covered by clouds in Delta on January 21 varies over the course of the day.

The cloudiest time of day is around 6:30 AM, at which time the chance of overcast or mostly cloudy conditions is 76%.

The clearest time of day is around 9:30 PM, at which time the chance of clear, mostly clear, or partly cloudy conditions is 30%.

For reference, on January 15, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 73%, while on August 2, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 72%.

Cloud Cover Categories on January 21

Cloud Cover Categories on January 21 in Deltanightdaynight12 AM3 AM6 AM9 AM12 PM3 PM6 PM9 PM12 AM0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%6:30 AM24%6:30 AM24%9:30 PM30%9:30 PM30%NowNowclearpartly cloudymostly cloudyovercastmostly clear
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds. Civil twilight and night are indicated by shaded overlays.

Precipitation

On average, there is a 50% chance that more than 0.04 inches of total precipitation will fall in Delta throughout the day on January 21, of which 84% is expected to be rain alone, 3% to be snow alone, and 13% to be a mixture of snow and rain.

For reference, the year's highest daily chance of precipitation is 59% on November 17, and its lowest chance is 10% on July 31.

For those 50% of years with precipitation on January 21, the chart below shows when throughout the day that precipitation is more or less likely to occur, excluding hourly accumulations of less than 0.01 inches. If precipitation were equally likely throughout the day, all hours would report 4.2% (100% divided by 24 hours).

Precipitation is most likely between 12 AM and 1 AM, and least likely between 7 PM and 8 PM.

Hourly Share of Precipitation on January 21

Hourly Share of Precipitation on January 21 in Delta nightdaynight12 AM3 AM6 AM9 AM12 PM3 PM6 PM9 PM12 AM0.0%0.5%1.0%1.5%2.0%2.5%3.0%3.5%4.0%4.5%4.2%4.2%12 AM4.4%12 AM4.4%7 PM3.9%7 PM3.9%NowNowrainsnowmixed
The share of the day's precipitation attributable to each hour of the day, excluding trace quantities, and color-coded as rain alone, snow alone, and mixed (both rain and snow fell during the same hour). Civil twilight and night are indicated by shaded overlays.

Sun

In Delta on Tuesday, January 21, 2020, the Sun rises at 7:55 AM and sets 8 hours, 54 minutes later, at 4:50 PM. Solar noon is at 12:23 PM.

For reference, on June 20, the longest day of the year, the Sun rises at 5:06 AM and sets 16 hours, 14 minutes later, at 9:20 PM, while on December 21, the shortest day of the year, it rises at 8:03 AM and sets 8 hours, 12 minutes later, at 4:16 PM.

Civil twilight, the period before the Sun has risen or after the Sun has set during which time it is possible to engage in most outdoor activities without artificial lighting, begins and ends 35 minutes before sunrise and after sunset, at 7:20 AM and 5:25 PM respectively.

Nautical twilight, during which time it is possible to clearly discern the horizon (e.g., for navigational purposes), begins and ends 1 hour, 15 minutes before sunrise and after sunset, at 6:41 AM and 6:04 PM respectively.

Astronomical twilight, outside of which it is possible to make the most sensitive of astronomical observations, begins and ends 1 hour, 52 minutes before sunrise and after sunset, at 6:03 AM and 6:42 PM respectively.

Solar Elevation on January 21, 2020

Solar Elevation on January 21, 2020 in Deltanightdaynight12 AM3 AM6 AM9 AM12 PM3 PM6 PM9 PM12 AM-60 deg-40 deg-20 deg0 deg20 deg40 deg60 degsolar noon12:23 PMsolar noon12:23 PM7:55 AMrise7:55 AMrise4:50 PMset4:50 PMsetsummer solsticesummer solsticewinter solsticewinter solsticeNowNow
Elevation of the center of the Sun above (positive) or below (negative) the horizon (black line). Yellow and gray fills indicate day and night, respectively. Light gray lines are the corresponding curves for the winter and summer solstices. Civil twilight and night are indicated by shaded overlays.

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.

Muggy conditions are essentially unheard-of in Delta on January 21.

Humidity Comfort Levels on January 21

Humidity Comfort Levels on January 21 in Delta nightdaynight12 AM3 AM6 AM9 AM12 PM3 PM6 PM9 PM12 AM0%10%20%30%40%50%60%70%80%90%100%12:30 PM0%12:30 PM0%NowNowdry
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The percentage of time spent at various humidity comfort levels, categorized by dew point. Civil twilight and night are indicated by shaded overlays.

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 Delta on January 21 varies throughout the day, with a daily average of 6.1 miles per hour.

The windiest time of day is around 5:30 AM, with an average hourly wind speed of 6.4 miles per hour, mostly staying between 5.0 miles per hour and 7.7 miles per hour, and rarely falling below 3.6 miles per hour or exceeding 9.5 miles per hour.

The calmest time of day is around 2:45 PM, with an average hourly wind speed of 5.3 miles per hour, mostly staying between 3.3 miles per hour and 6.8 miles per hour, and rarely falling below 2.1 miles per hour or exceeding 9.2 miles per hour.

For reference, on December 3, the windiest day of the year, the daily average wind speed is 6.5 miles per hour, while on August 8, the calmest day of the year, the daily average wind speed is 2.8 miles per hour.

Wind Speed on January 21

Wind Speed on January 21 in Delta nightdaynight12 AM3 AM6 AM9 AM12 PM3 PM6 PM9 PM12 AM0 mph1 mph2 mph3 mph4 mph5 mph6 mph7 mph8 mph9 mph5:30 AM6.4 mph5:30 AM6.4 mph5.3 mph2:45 PM5.3 mph2:45 PMNowNow
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands. Civil twilight and night are indicated by shaded overlays.

Over the entire course of January 21 in Delta, the hourly average wind direction, in order of prevalence, is from the east (49%), south (24%), north (19%), and west (8%).

Wind Direction on January 21

Wind Direction on January 21 in Delta nightdaynight12 AM3 AM6 AM9 AM12 PM3 PM6 PM9 PM12 AM0%100%20%80%40%60%60%40%80%20%100%0%NowNowsoutheastnorthwest
northeastsouthwest
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest). Civil twilight and night are indicated by shaded overlays.

Water Temperature

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 surface water temperature does not change appreciably over the course of the day, so this section does not include a chart.

The average surface water temperature on January 21 in Delta is 45°F, mostly staying between 44°F and 45°F, and rarely falling below 43°F or exceeding 46°F.

For reference, the year's highest average is 60°F on August 2, and its lowest average is 45°F on January 30.

Shortwave Solar Power

This section discusses the incident shortwave solar power 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 peak incident shortwave solar power per square meter is 0.20 kilowatts at around 12:15 PM.

In contrast, the corresponding value on July 19, the brightest day of the year, is 0.75 kilowatts at around 12:15 PM. The corresponding value on December 24, the darkest day of the year, is 0.16 kilowatts at around 11:15 AM.

Shortwave Solar Power on January 21

Shortwave Solar Power on January 21 in Delta nightdaynight12 AM3 AM6 AM9 AM12 PM3 PM6 PM9 PM12 AM0.0 kW0.5 kW1.0 kW1.5 kW12:15 PM0.20 kW12:15 PM0.20 kWJul 19Jul 19NowNow
Average incident shortwave solar power reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands. Light gray lines are the corresponding curves for the days with the minimum and maximum average total solar energy reaching the ground. Civil twilight and night are indicated by shaded overlays.

Topography

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%).

Data Sources

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 3 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: Boundary Bay Airport (60%, 7 kilometers, west); White Rock Automatic Weather Reporting System (20%, 17 kilometers, southeast); and P. Meadows Coastal Station Automatic Weather Reporting System (20%, 17 kilometers, east).

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , 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.

We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.