Thornlie in Summer
In summer (December, January and February), Thornlie sees average daytime highs around 30°C and overnight lows near 18°C, with 47 mm of rain over about 6 wet days across the season. It is the warmest season of the year and the driest season of the year.
Over the season highs climb from about 27°C in early December to 31°C by late February. The sky is clear or mostly clear about 73% of the time across summer, and the air most often feels dry.
Summer is Thornlie's 3rd-best season to visit on our travel score. For the whole year in context, see Thornlie's year-round climate.
- Avg daytime high
- 30°C
- warmest season of the year
- Avg overnight low
- 18°C
- Rainfall
- 47 mm
- 6 wet days
- Avg wind
- 16 km/h
- Travel score
- 6.2
- 3rd-best season
- Months
- Dec · Jan · Feb
Temperature in Thornlie in Summer
Over the season highs climb from about 27°C in early December to 31°C by late February.
A typical summer day in Thornlie reaches about 30°C and drops to 18°C overnight. The warmest of the three months is January, the coolest December.
Thornlie weather by month
How the three summer months (December, January and February) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 31° / 18° | 19 | 2.1 | 13.9 | 5.7 |
| Feb | 31° / 19° | 17 | 1.7 | 13.2 | 5.7 |
| Mar | 29° / 17° | 18 | 2.7 | 12.2 | 7.0 |
| Apr | 25° / 14° | 26 | 4 | 11.2 | 8.0 |
| May | 21° / 11° | 62 | 7 | 10.4 | 7.1 |
| Jun | 18° / 9° | 87 | 10 | 9.9 | 6.0 |
| Jul | 17° / 9° | 96 | 11.6 | 10.1 | 5.3 |
| Aug | 17° / 9° | 87 | 10.7 | 10.8 | 5.7 |
| Sep | 19° / 9° | 60 | 8.7 | 11.8 | 6.4 |
| Oct | 22° / 11° | 29 | 5 | 12.8 | 7.8 |
| Nov | 26° / 14° | 22 | 4 | 13.6 | 8.1 |
| Dec | 29° / 16° | 11 | 1.9 | 14.1 | 7.1 |
Cloud cover in Summer
The sky is clear or mostly clear about 73% of the time across summer.
Chance of precipitation in Summer
Thornlie gets around 47 mm of rain over 6 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 16 km/h across summer.
Sunrise & sunset in Summer
Daylight runs from about 13 h 54 min in early December to 12 h 48 min by late February. The lit band spans sunrise to sunset each day.
Solar energy in Summer
Average shortwave solar energy reaching the ground each day across summer, about 8.0 kWh/m².
Hazard calendar for Thornlie
In summer, Thornlie overlaps its cyclone season. The full year is below, with each hazard's peak months called out.
Thornlie sits in the South Indian Ocean cyclone belt; the season peaks January–March.
Thornlie's rainy season runs May–September, when most of the year's rain falls.
Is summer a good time to visit Thornlie?
Our two travel scores rate summer for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
summer is a reasonable time to visit Thornlie for sightseeing. The water and warmth also suit a beach or pool day.
What to pack for Thornlie in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Thornlie sees daytime highs around 30°C and nights near 18°C. Pack light clothes and sun protection. About 6 days see rain.
Sea temperature near Thornlie in Summer
The nearest coast averages about 22°C across summer — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 32 km away) is warmest in February at about 22°C and coldest in September near 19°C.
It's comfortable for a long swim from Nov 26 to Jul 9 — about 7.4 months when the water holds above 20°C.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 22 | 22 | 22 | 22 | 22 | 21 | 20 | 19 | 19 | 19 | 20 | 21 |
| Comfort | Refreshing | Refreshing | Refreshing | Refreshing | Refreshing | Refreshing | Cool | Cool | Cool | Cool | Cool | Refreshing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 22 | Refreshing |
| Feb | 22 | Refreshing |
| Mar | 22 | Refreshing |
| Apr | 22 | Refreshing |
| May | 22 | Refreshing |
| Jun | 21 | Refreshing |
| Jul | 20 | Cool |
| Aug | 19 | Cool |
| Sep | 19 | Cool |
| Oct | 19 | Cool |
| Nov | 20 | Cool |
| Dec | 21 | Refreshing |
UV index in Thornlie in Summer
Clear-sky midday UV across summer averages around 13 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Thornlie peaks around December 23 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 21 at about 3 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 13 | 12 | 11 | 6 | 4 | 3 | 3 | 5 | 8 | 9 | 10 | 13 |
| Level | Extreme | Extreme | Extreme | High | Moderate | Moderate | Moderate | Moderate | Very high | Very high | Extreme | Extreme |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 13 | Extreme |
| Feb | 12 | Extreme |
| Mar | 11 | Extreme |
| Apr | 6 | High |
| May | 4 | Moderate |
| Jun | 3 | Moderate |
| Jul | 3 | Moderate |
| Aug | 5 | Moderate |
| Sep | 8 | Very high |
| Oct | 9 | Very high |
| Nov | 10 | Extreme |
| Dec | 13 | Extreme |
Air quality in Thornlie in Summer
Average fine-particle pollution (PM2.5) through the year — so you can see where summer falls, not just the annual average.
Air quality in Thornlie is worst in May — around 18 µg/m³ PM2.5 (moderate), about 4.4× the cleanest month (December, 4 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 8 | 7 | 5 | 10 | 18 | 8 | 6 | 7 | 15 | 15 | 10 | 4 |
| Level | Good | Good | Good | Good | Moderate | Good | Good | Good | Moderate | Moderate | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 8 | Good |
| Feb | 7 | Good |
| Mar | 5 | Good |
| Apr | 10 | Good |
| May | 18 | Moderate |
| Jun | 8 | Good |
| Jul | 6 | Good |
| Aug | 7 | Good |
| Sep | 15 | Moderate |
| Oct | 15 | Moderate |
| Nov | 10 | Good |
| Dec | 4 | Good |
Where is Thornlie?
Thornlie sits at 32.1°S, 116.0°E, 19 m above sea level, in Australia. The nearest listed city is Canning Vale, 3.0 km away.
Topography around Thornlie
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Thornlie.
Within 3 km, the terrain around Thornlie has only modest variations in elevation — a maximum elevation change of 27 m around an average of 16 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 378 m; within 80 km, significant variations in elevation — a maximum elevation change of 567 m.
The land around Thornlie is covered by artificial surfaces (74%) within 3 km, artificial surfaces (40%) and trees (39%) within 16 km, and trees (43%) and water (29%) within 80 km.
Australia travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type I
- 230 V · 50 Hz
- Prices
- ≈ 90% of US
- price level, 2025
- GDP per capita
- $65,130
- 2025
- Happiness
- 6.9 / 10
- World Happiness, 2025
- Homicide rate
- 0.9
- per 100k, 2023
- Road deaths
- 4.9
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Thornlie (-32.06°, 115.955°, elevation 19 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.