Castle Hill in Spring
In spring (September, October and November), Castle Hill sees average daytime highs around 23°C and overnight lows near 12°C, with 154 mm of rain over about 22 wet days across the season. It is the 2nd-warmest season and the 3rd-wettest season.
Over the season highs climb from about 20°C in early September to 26°C by late November. The sky is clear or mostly clear about 41% of the time across spring, and the air most often feels dry.
Spring is Castle Hill's best season of the year to visit on our travel score. For the whole year in context, see Castle Hill's year-round climate.
- Avg daytime high
- 23°C
- 2nd-warmest season
- Avg overnight low
- 12°C
- Rainfall
- 154 mm
- 22 wet days
- Avg wind
- 11 km/h
- Travel score
- 7.3
- best season of the year
- Months
- Sep · Oct · Nov
Temperature in Castle Hill in Spring
Over the season highs climb from about 20°C in early September to 26°C by late November.
A typical spring day in Castle Hill reaches about 23°C and drops to 12°C overnight. The warmest of the three months is November, the coolest September.
Castle Hill weather by month
How the three spring months (September, October and November) 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 | 28° / 19° | 66 | 9.1 | 14 | 6.2 |
| Feb | 27° / 19° | 84 | 10 | 13.3 | 6.3 |
| Mar | 26° / 17° | 66 | 10.6 | 12.3 | 6.8 |
| Apr | 23° / 13° | 51 | 7.8 | 11.2 | 7.4 |
| May | 20° / 10° | 45 | 6.3 | 10.3 | 7.1 |
| Jun | 18° / 8° | 61 | 7.4 | 9.8 | 6.3 |
| Jul | 17° / 7° | 35 | 5.7 | 10 | 6.5 |
| Aug | 19° / 7° | 35 | 5.2 | 10.7 | 7.2 |
| Sep | 22° / 10° | 39 | 6.1 | 11.8 | 7.5 |
| Oct | 24° / 13° | 49 | 7.3 | 12.8 | 7.5 |
| Nov | 25° / 15° | 66 | 8.6 | 13.8 | 7.0 |
| Dec | 27° / 17° | 58 | 8.7 | 14.2 | 6.7 |
Cloud cover in Spring
The sky is clear or mostly clear about 41% of the time across spring.
Chance of precipitation in Spring
Castle Hill gets around 154 mm of rain over 22 wet days across spring. The line is the day-by-day chance of measurable precipitation.
Humidity in Spring
Most of spring feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Spring
Winds average 11 km/h across spring.
Sunrise & sunset in Spring
Daylight runs from about 11 h 18 min in early September to 14 h 06 min by late November. The lit band spans sunrise to sunset each day.
Solar energy in Spring
Average shortwave solar energy reaching the ground each day across spring, about 5.6 kWh/m².
Hazard calendar for Castle Hill
In spring, Castle Hill overlaps its cyclone season. The full year is below, with each hazard's peak months called out.
Castle Hill sits in the South Indian Ocean cyclone belt; the season peaks January–March.
Is spring a good time to visit Castle Hill?
Our two travel scores rate spring for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
spring is one of the better times to visit Castle Hill for general sightseeing.
What to pack for Castle Hill in Spring
From spring's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In spring, Castle Hill sees daytime highs around 23°C and nights near 12°C. Pack sun protection. Worth having: light clothes and rain gear. About 22 days see rain.
Sea temperature near Castle Hill in Spring
The nearest coast averages about 19°C across spring — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 37 km away) is warmest in February at about 23°C and coldest in August near 18°C.
It's comfortable for a long swim from Nov 16 to Jun 4 — about 6.6 months when the water holds above 20°C.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 23 | 23 | 23 | 22 | 21 | 20 | 19 | 18 | 18 | 19 | 20 | 21 |
| Comfort | Refreshing | Refreshing | Refreshing | Refreshing | Refreshing | Cool | Cool | Cool | Cool | Cool | Refreshing | Refreshing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 23 | Refreshing |
| Feb | 23 | Refreshing |
| Mar | 23 | Refreshing |
| Apr | 22 | Refreshing |
| May | 21 | Refreshing |
| Jun | 20 | Cool |
| Jul | 19 | Cool |
| Aug | 18 | Cool |
| Sep | 18 | Cool |
| Oct | 19 | Cool |
| Nov | 20 | Refreshing |
| Dec | 21 | Refreshing |
UV index in Castle Hill in Spring
Clear-sky midday UV across spring averages around 8 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Castle Hill peaks around January 16 at about 12 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 19 at about 2 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 12 | 11 | 9 | 6 | 4 | 2 | 3 | 4 | 6 | 8 | 10 | 12 |
| Level | Extreme | Extreme | Very high | High | Moderate | Moderate | Moderate | Moderate | High | Very high | Very high | Extreme |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 12 | Extreme |
| Feb | 11 | Extreme |
| Mar | 9 | Very high |
| Apr | 6 | High |
| May | 4 | Moderate |
| Jun | 2 | Moderate |
| Jul | 3 | Moderate |
| Aug | 4 | Moderate |
| Sep | 6 | High |
| Oct | 8 | Very high |
| Nov | 10 | Very high |
| Dec | 12 | Extreme |
Air quality in Castle Hill in Spring
Average fine-particle pollution (PM2.5) through the year — so you can see where spring falls, not just the annual average.
Air quality in Castle Hill is worst in December — around 49 µg/m³ PM2.5 (poor), about 8.1× the cleanest month (June, 6 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) | 11 | 7 | 7 | 8 | 8 | 6 | 6 | 8 | 10 | 10 | 25 | 49 |
| Level | Good | Good | Good | Good | Good | Good | Good | Good | Good | Good | Moderate | Poor |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 11 | Good |
| Feb | 7 | Good |
| Mar | 7 | Good |
| Apr | 8 | Good |
| May | 8 | Good |
| Jun | 6 | Good |
| Jul | 6 | Good |
| Aug | 8 | Good |
| Sep | 10 | Good |
| Oct | 10 | Good |
| Nov | 25 | Moderate |
| Dec | 49 | Poor |
Where is Castle Hill?
Castle Hill sits at 33.7°S, 151.0°E, 126 m above sea level, in Australia. The nearest listed city is Baulkham Hills, 3.0 km away.
Topography around Castle Hill
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Castle Hill.
Within 3 km, the terrain around Castle Hill has only modest variations in elevation — a maximum elevation change of 139 m around an average of 118 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 251 m; within 80 km, large variations in elevation — a maximum elevation change of 1,191 m.
The land around Castle Hill is covered by trees (64%) and artificial surfaces (31%) within 3 km, trees (55%) and artificial surfaces (32%) within 16 km, and trees (61%) and water (26%) 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 Castle Hill (-33.7333°, 151°, elevation 126 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.