Climate and Average Weather Year Round in Roxby Downs South Australia, Australia

In Roxby Downs, the summers are hot and windy, the winters are cool, and it is dry and mostly clear year round. Over the course of the year, the temperature typically varies from 44°F to 95°F and is rarely below 39°F or above 106°F.

Based on the tourism score, the best time of year to visit Roxby Downs for warm-weather activities is from late October to mid April.

The hot season lasts for 3.5 months, from November 25 to March 11, with an average daily high temperature above 88°F. The hottest month of the year in Roxby Downs is January, with an average high of 95°F and low of 71°F.

The cool season lasts for 3.2 months, from May 19 to August 24, with an average daily high temperature below 69°F. The coldest month of the year in Roxby Downs is July, with an average low of 45°F and high of 63°F.

In Roxby Downs, 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 Roxby Downs begins around June 29 and lasts for 3.6 months, ending around October 15.

The clearest month of the year in Roxby Downs is August, during which on average the sky is clear, mostly clear, or partly cloudy 87% of the time.

The cloudier part of the year begins around October 15 and lasts for 8.4 months, ending around June 29.

The cloudiest month of the year in Roxby Downs is November, during which on average the sky is overcast or mostly cloudy 30% of the time.

Roxby Downs does not experience significant seasonal variation in the frequency of wet days (i.e., those with greater than 0.04 inches of liquid or liquid-equivalent precipitation). The frequency ranges from 4% to 9%, with an average value of 6%.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. The month with the most days of rain alone in Roxby Downs is May, with an average of 2.1 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 9% on May 30.

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. Roxby Downs experiences some seasonal variation in monthly rainfall.

The rainy period of the year lasts for 6.5 months, from November 24 to June 9, with a sliding 31-day rainfall of at least 0.5 inches. The month with the most rain in Roxby Downs is February, with an average rainfall of 0.7 inches.

The rainless period of the year lasts for 5.5 months, from June 9 to November 24. The month with the least rain in Roxby Downs is July, with an average rainfall of 0.3 inches.

The length of the day in Roxby Downs varies significantly over the course of the year. In 2024, the shortest day is June 21, with 10 hours, 10 minutes of daylight; the longest day is December 21, with 14 hours, 8 minutes of daylight.

The earliest sunrise is at 5:55 AM on October 5, and the latest sunrise is 1 hour, 41 minutes later at 7:36 AM on April 6. The earliest sunset is at 5:28 PM on June 10, and the latest sunset is 3 hours, 1 minute later at 8:29 PM on January 10.

Daylight saving time (DST) is observed in Roxby Downs during 2024, starting in the spring on October 6 and ending in the fall on April 7.

The figure below presents a compact representation of key lunar data for 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases.

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 Roxby Downs, 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 2% of 2% 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 Roxby Downs experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 6.9 months, from August 17 to March 15, with average wind speeds of more than 10.2 miles per hour. The windiest month of the year in Roxby Downs is October, with an average hourly wind speed of 11.7 miles per hour.

The calmer time of year lasts for 5.1 months, from March 15 to August 17. The calmest month of the year in Roxby Downs is May, with an average hourly wind speed of 8.6 miles per hour.

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

The wind is most often from the north for 1.6 months, from June 17 to August 6, with a peak percentage of 32% on July 23. The wind is most often from the south for 10 months, from August 6 to June 17, with a peak percentage of 50% on January 1.

To characterize how pleasant the weather is in Roxby Downs throughout the year, we compute two travel scores.

The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit Roxby Downs for general outdoor tourist activities is from late October to mid April, with a peak score in the second week of March.

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Roxby Downs for hot-weather activities is from mid December to early March, with a peak score in the second week of January.

Methodology

For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.

Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.

Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.

Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.

Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

Temperatures in Roxby Downs are sufficiently warm year round that it is not entirely meaningful to discuss the growing season in these terms. We nevertheless include the chart below as an illustration of the distribution of temperatures experienced throughout the year.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°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 3.7 months, from October 28 to February 19, with an average daily incident shortwave energy per square meter above 7.5 kWh. The brightest month of the year in Roxby Downs is December, with an average of 8.4 kWh.

The darker period of the year lasts for 3.2 months, from May 2 to August 7, with an average daily incident shortwave energy per square meter below 4.3 kWh. The darkest month of the year in Roxby Downs is June, with an average of 3.3 kWh.

For the purposes of this report, the geographical coordinates of Roxby Downs are -30.563 deg latitude, 136.895 deg longitude, and 351 ft elevation.

The topography within 2 miles of Roxby Downs contains only modest variations in elevation, with a maximum elevation change of 108 feet and an average elevation above sea level of 359 feet. Within 10 miles also contains only modest variations in elevation (315 feet). Within 50 miles contains only modest variations in elevation (741 feet).

The area within 2 miles of Roxby Downs is covered by sparse vegetation (80%) and artificial surfaces (19%), within 10 miles by sparse vegetation (83%) and grassland (12%), and within 50 miles by sparse vegetation (77%) and grassland (13%).