Dee Why in Summer
In summer (December, January and February), Dee Why sees average daytime highs around 24°C and overnight lows near 20°C, with 225 mm of rain over about 28 wet days across the season. It is the warmest season of the year and the 2nd-wettest season.
Across summer, daytime highs hold fairly steady around 24°C. The sky is clear or mostly clear about 39% of the time across summer, and the air most often feels muggy.
Summer is Dee Why's best season of the year to visit on our travel score. For the whole year in context, see Dee Why's year-round climate.
- Avg daytime high
- 24°C
- warmest season of the year
- Avg overnight low
- 20°C
- Rainfall
- 225 mm
- 28 wet days
- Avg wind
- 18 km/h
- Travel score
- 7.1
- best season of the year
- Months
- Dec · Jan · Feb
Temperature in Dee Why in Summer
Across summer, daytime highs hold fairly steady around 24°C.
A typical summer day in Dee Why reaches about 24°C and drops to 20°C overnight. The warmest of the three months is January, the coolest December.
Dee Why 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 | 24° / 20° | 72 | 9.3 | 14 | 7.2 |
| Feb | 24° / 20° | 93 | 10.3 | 13.3 | 6.9 |
| Mar | 23° / 19° | 82 | 11.6 | 12.3 | 6.8 |
| Apr | 21° / 17° | 77 | 10.5 | 11.2 | 6.7 |
| May | 19° / 14° | 79 | 9.7 | 10.3 | 6.4 |
| Jun | 17° / 12° | 97 | 10.3 | 9.8 | 5.6 |
| Jul | 16° / 11° | 56 | 7.7 | 10 | 5.8 |
| Aug | 17° / 11° | 53 | 6.6 | 10.7 | 6.4 |
| Sep | 19° / 13° | 50 | 6.7 | 11.8 | 6.9 |
| Oct | 20° / 15° | 59 | 8 | 12.8 | 6.8 |
| Nov | 21° / 17° | 72 | 9.1 | 13.8 | 6.8 |
| Dec | 23° / 19° | 60 | 8.6 | 14.2 | 7.2 |
Cloud cover in Summer
The sky is clear or mostly clear about 39% of the time across summer.
Chance of precipitation in Summer
Dee Why gets around 225 mm of rain over 28 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels muggy — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 18 km/h across summer.
Sunrise & sunset in Summer
Daylight runs from about 14 h 06 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 6.3 kWh/m².
Hazard calendar for Dee Why
In summer, Dee Why overlaps its cyclone season. The full year is below, with each hazard's peak months called out.
Dee Why sits in the South Indian Ocean cyclone belt; the season peaks January–March.
Is summer a good time to visit Dee Why?
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 one of the better times to visit Dee Why for general sightseeing.
What to pack for Dee Why in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Dee Why sees daytime highs around 24°C and nights near 20°C. Pack sun protection. Worth having: light clothes and rain gear. About 28 days see rain.
Sea temperature near Dee Why in Summer
The nearest coast averages about 23°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 16 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 13 to Jun 7 — about 6.8 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 Dee Why in Summer
Clear-sky midday UV across summer averages around 12 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Dee Why 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 |
Where is Dee Why?
Dee Why sits at 33.8°S, 151.3°E, 18 m above sea level, in Australia. The nearest listed city is Manly, 5.0 km away.
Topography around Dee Why
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Dee Why.
Within 3 km, the terrain around Dee Why has only modest variations in elevation — a maximum elevation change of 170 m around an average of 31 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 223 m; within 80 km, large variations in elevation — a maximum elevation change of 811 m.
The land around Dee Why is covered by artificial surfaces (34%), trees (30%) and water (28%) within 3 km, water (52%) and trees (36%) within 16 km, and trees (50%) and water (36%) 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 Dee Why (-33.7511°, 151.2889°, elevation 18 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.