Thornlie Temperature by Month

Thornlie in Western Australia, Australia sees significant seasonal temperature differences, with daytime highs between 18°C (64°F) in July and 32°C (90°F) in January, averaging 25°C (77°F) annually. Explore the full monthly breakdown below.

Visitors to Thornlie will encounter a climate influenced by big temperature differences across the year. Nighttime temperatures range from 18°C (64°F) in January to 9°C (48°F) in July.

The chart below illustrates the average maximum day and minimum night temperatures in Thornlie by month:

Temperatures tend to bottom out between 4 AM and 6 AM, then climb to their daily peak around 3 PM. January, the warmest month, sees 355 hours of sunshine.

The chart below shows the average temperature throughout the year:

Thornlie's average annual maximum temperature is 25°C (77°F). To put that in context, here's how it compares to a few well-known destinations:

Lisbon, Portugal averages 21°C (70°F) annually, warm summers, mild winters, and rain mainly in the cooler months.

Reykjavík, Iceland averages 9°C (48°F) a year, mild summers by Icelandic standards, but cold winters and frequent wind.

Beijing, China averages 20°C (68°F) annually, but with big seasonal swings, very cold winters and hot summers.

Adelaide, Australia averages 21°C (70°F) a year, with warm summers, mild winters, and relatively low rainfall year-round.

Temperature alone doesn't tell the whole story, humidity plays a big role in how warm or cold it actually feels. High humidity in summer makes the heat feel more intense, particularly once temperatures climb above 25°C. In winter, the same humidity can make cold air feel sharper than the thermometer suggests.

In Thornlie, July is the coolest month, with average highs of 18°C (64°F) and humidity around 57%, considered moderate. In January, the warmest month, temperatures average 32°C (90°F) with 39% humidity, conditions that feel low. For a full picture, see our humidity page.

Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.

The readings come from a range of sources, land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.

Seasonal temperature shifts influence more than just how warm it feels, they also drive changes in rainfall, cloud cover, and wind patterns throughout the year.

Warmer air holds more moisture, which tends to mean heavier or more frequent rain during the warmer months. When temperatures drop in winter, any precipitation that does fall is more likely to come as snow or sleet, though in Thornlie this rarely lasts long on the ground.

For more on Thornlie's weather, including monthly rainfall, sunshine hours, and humidity, visit our Thornlie climate page.