Average Weather in Williamstown Australia

1. World
2. Australia
3. South Australia
4. Barossa
5. Williamstown

In Williamstown, the summers are warm and dry, the winters are cold, and it is mostly clear year round. Over the course of the year, the temperature typically varies from 40°F to 85°F and is rarely below 33°F or above 101°F.

The warm season lasts for 3.3 months, from December 3 to March 13, with an average daily high temperature above 79°F. The hottest day of the year is January 24, with an average high of 85°F and low of 60°F.

The cool season lasts for 3.4 months, from May 23 to September 5, with an average daily high temperature below 61°F. The coldest day of the year is July 20, with an average low of 40°F and high of 55°F.

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.

In Williamstown, the average percentage of the sky covered by clouds experiences mild seasonal variation over the course of the year.

The clearer part of the year in Williamstown begins around December 13 and lasts for 3.8 months, ending around April 6. On February 8, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 76% of the time, and overcast or mostly cloudy 24% of the time.

The cloudier part of the year begins around April 6 and lasts for 8.2 months, ending around December 13. On June 1, the cloudiest day of the year, the sky is overcast or mostly cloudy 39% of the time, and clear, mostly clear, or partly cloudy 61% 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 Williamstown varies throughout the year.

The wetter season lasts 5.2 months, from May 3 to October 9, with a greater than 17% chance of a given day being a wet day. The chance of a wet day peaks at 28% on July 2.

The drier season lasts 6.8 months, from October 9 to May 3. The smallest chance of a wet day is 5% on February 10.

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 28% on July 2.

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. Williamstown experiences some seasonal variation in monthly rainfall.

Rain falls throughout the year in Williamstown. The most rain falls during the 31 days centered around June 22, with an average total accumulation of 1.8 inches.

The least rain falls around January 15, with an average total accumulation of 0.5 inches.

The length of the day in Williamstown varies significantly over the course of the year. In 2017, the shortest day is June 21, with 9 hours, 50 minutes of daylight; the longest day is December 21, with 14 hours, 29 minutes of daylight.

The earliest sunrise is at 5:52 AM on September 30, and the latest sunrise is 1 hour, 34 minutes later at 7:26 AM on April 1. The earliest sunset is at 5:09 PM on June 12, and the latest sunset is 3 hours, 21 minutes later at 8:31 PM on January 7.

Daylight saving time (DST) is observed in Williamstown during 2017, starting in the spring on October 1 and ending in the fall on April 2.

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 Williamstown, 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 1% of 1% throughout.

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 Williamstown experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 5.6 months, from September 26 to March 15, with average wind speeds of more than 5.2 miles per hour. The windiest day of the year is January 25, with an average hourly wind speed of 6.0 miles per hour.

The calmer time of year lasts for 6.4 months, from March 15 to September 26. The calmest day of the year is May 20, with an average hourly wind speed of 4.6 miles per hour.

The predominant average hourly wind direction in Williamstown varies throughout the year.

The wind is most often from the west for 1.6 weeks, from May 1 to May 12 and for 4.1 months, from June 17 to October 19, with a peak percentage of 43% on August 10. The wind is most often from the north for 1.2 months, from May 12 to June 17, with a peak percentage of 34% on June 15. The wind is most often from the south for 6.4 months, from October 19 to May 1, with a peak percentage of 51% on January 1.

Williamstown 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 3.4 months, from December 23 to April 6, with an average temperature above 67°F. The day of the year with the warmest water is February 14, with an average temperature of 71°F.

The time of year with cooler water lasts for 3.5 months, from June 19 to October 2, with an average temperature below 59°F. The day of the year with the coolest water is August 11, with an average temperature of 55°F.

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 3.6 months, from November 4 to February 20, with an average daily incident shortwave energy per square meter above 7.2 kWh. The brightest day of the year is January 4, with an average of 8.4 kWh.

The darker period of the year lasts for 3.5 months, from May 1 to August 17, with an average daily incident shortwave energy per square meter below 3.6 kWh. The darkest day of the year is June 19, with an average of 2.4 kWh.

For the purposes of this report, the geographical coordinates of Williamstown are -34.672 deg latitude, 138.891 deg longitude, and 945 ft elevation.

The topography within 2 miles of Williamstown contains significant variations in elevation, with a maximum elevation change of 755 feet and an average elevation above sea level of 1,001 feet. Within 10 miles contains significant variations in elevation (1,923 feet). Within 50 miles contains very significant variations in elevation (2,431 feet).

The area within 2 miles of Williamstown is covered by trees (37%), cropland (37%), and sparse vegetation (16%), within 10 miles by cropland (51%) and trees (28%), and within 50 miles by cropland (50%) and sparse vegetation (16%).

This report illustrates the typical weather in Williamstown, 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 is only a single weather station, RAAF Base Edinburgh, in our network suitable to be used as a proxy for the historical temperature and dew point records of Williamstown.

At a distance of 25 kilometers from Williamstown, closer than our threshold of 150 kilometers, this station is deemed sufficiently nearby to be relied upon as our primary source for temperature and dew point records.

The station records are corrected for the elevation difference between the station and Williamstown according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.

Please note that the station records themselves may additionally have been back-filled using other nearby stations or the MERRA-2 reanalysis.

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.