Dee Why weather in September

In September, Dee Why sees average daytime highs of 19°C and overnight lows near 13°C, with 50 mm of rain across 6.7 wet days and about 11.8 hours of daylight. It is the 9th-warmest and 12th-wettest month of the year here.

Highs climb over the month, from about 18°C in the first days to 20°C by the end. The sky is clear or mostly clear about 58% of the time in September, and the air most often feels dry.

Daylight stretches from about 11 h 18 min at the start of September to 12 h 18 min by month's end. Set against the rest of the year, September is Dee Why's 3rd-clearest and 5th-windiest month. For the whole year in context, see Dee Why's year-round climate.

Daytime high: 19°; 9th warmest
Overnight low: 13°; 4th coldest
Rainfall: 50 mm; 6.7 wet days
Daylight: 11 h 48 min; 6:55 AM – 6:43 PM
Cloud cover: 37%; 3rd clearest
Wind: 18 km/h; 5th windiest
Solar energy: 4.91 kWh/m²
Travel score: 6.9; out of 10

Dee Why is suburb of Sydney, New South Wales, Australia.

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

← August Dee Why year-round climate October →Best places to visit in September

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 18°C in the first days to 20°C by the end.

A typical September day in Dee Why reaches about 19°C in the afternoon and slips back to 13°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 16°C and 23°C. Set against its neighbours, September runs about 2°C warmer than August and about 1°C cooler than October.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Avg high (°C)	18	18	18	18	18	18	18	18	18	18	19	19	19	19	19	19	19	19	19	19	19	19	19	20	20	20	20	20	20	20
Avg low (°C)	12	12	12	13	13	13	13	13	13	13	13	13	13	13	13	13	13	13	13	14	14	14	14	14	14	14	14	14	14	14

	Avg high (°C)	Avg low (°C)
1	18	12
2	18	12
3	18	12
4	18	13
5	18	13
6	18	13
7	18	13
8	18	13
9	18	13
10	18	13
11	19	13
12	19	13
13	19	13
14	19	13
15	19	13
16	19	13
17	19	13
18	19	13
19	19	13
20	19	14
21	19	14
22	19	14
23	19	14
24	20	14
25	20	14
26	20	14
27	20	14
28	20	14
29	20	14
30	20	14

Dee Why weather by month

How September compares with the rest of the year at a glance. September is the 9th-warmest and 12th-wettest month here — the current month is highlighted below.

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 September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 58% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 18% of September, with mostly cloudy or overcast conditions the remaining 25%.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Clearer (%)	74	74	74	74	75	76	76	76	76	77	77	77	77	78	78	78	76	76	76	76	76	76	75	74	74	73	73	72	72	71
Cloudier (%)	26	26	26	26	25	24	24	24	24	23	23	23	23	22	22	22	24	24	24	24	24	24	25	26	26	27	27	28	28	29

	Clearer (%)	Cloudier (%)
1	74	26
2	74	26
3	74	26
4	74	26
5	75	25
6	76	24
7	76	24
8	76	24
9	76	24
10	77	23
11	77	23
12	77	23
13	77	23
14	78	22
15	78	22
16	78	22
17	76	24
18	76	24
19	76	24
20	76	24
21	76	24
22	76	24
23	75	25
24	74	26
25	74	26
26	73	27
27	73	27
28	72	28
29	72	28
30	71	29

Chance of precipitation in September

Any precipitation

Dee Why gets around 50 mm of rain over 6.7 wet days in September, the driest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 23% and peaks near 26% on the wettest days.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Rain chance (%)	26	26	26	26	26	26	25	25	24	24	23	23	23	22	22	21	21	21	21	21	20	20	20	20	20	21	21	21	22	22

	Rain chance (%)
1	26
2	26
3	26
4	26
5	26
6	26
7	25
8	25
9	24
10	24
11	23
12	23
13	23
14	22
15	22
16	21
17	21
18	21
19	21
20	21
21	20
22	20
23	20
24	20
25	20
26	21
27	21
28	21
29	22
30	22

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the dry band about 85% of days. It rarely turns muggy — the humid and sticky bands barely register.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Dry (%)	91	91	90	90	90	90	90	90	90	90	89	89	88	87	86	86	85	84	83	82	82	81	80	79	79	78	76	75	74	74
Comfortable (%)	9	9	10	10	10	10	10	10	10	10	11	11	11	12	13	13	14	15	15	16	16	17	17	18	18	19	20	21	22	22
Humid (%)	0	0	0	0	0	0	0	0	0	0	0	0	1	1	1	1	1	1	2	2	2	2	3	3	3	3	4	4	4	4

	Dry (%)	Comfortable (%)	Humid (%)
1	91	9	0
2	91	9	0
3	90	10	0
4	90	10	0
5	90	10	0
6	90	10	0
7	90	10	0
8	90	10	0
9	90	10	0
10	90	10	0
11	89	11	0
12	89	11	0
13	88	11	1
14	87	12	1
15	86	13	1
16	86	13	1
17	85	14	1
18	84	15	1
19	83	15	2
20	82	16	2
21	82	16	2
22	81	17	2
23	80	17	3
24	79	18	3
25	79	18	3
26	78	19	3
27	76	20	4
28	75	21	4
29	74	22	4
30	74	22	4

Wind in September

Winds average 18 km/h in September.

Across September, daily wind ranges from about 18 km/h on the calmest days to 18 km/h at its breeziest. It stays fairly steady from day to day.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Wind speed (km/h)	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18
Feels	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze

	Wind speed (km/h)	Feels
1	18	light breeze
2	18	light breeze
3	18	light breeze
4	18	light breeze
5	18	light breeze
6	18	light breeze
7	18	light breeze
8	18	light breeze
9	18	light breeze
10	18	light breeze
11	18	light breeze
12	18	light breeze
13	18	light breeze
14	18	light breeze
15	18	light breeze
16	18	light breeze
17	18	light breeze
18	18	light breeze
19	18	light breeze
20	18	light breeze
21	18	light breeze
22	18	light breeze
23	18	light breeze
24	18	light breeze
25	18	light breeze
26	18	light breeze
27	18	light breeze
28	18	light breeze
29	18	light breeze
30	18	light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 11 h 18 min at the start of September to 12 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 60 minutes over September. Sunrise moves from 7:17 AM to 6:35 AM, and sunset from 6:32 PM to 6:53 PM.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Daylight (h)	11.3	11.3	11.3	11.4	11.4	11.4	11.5	11.5	11.5	11.6	11.6	11.7	11.7	11.7	11.8	11.8	11.8	11.9	11.9	11.9	12.0	12.0	12.0	12.1	12.1	12.2	12.2	12.2	12.3	12.3
Sunrise (AM)	7:17	7:15	7:14	7:12	7:11	7:10	7:08	7:07	7:05	7:04	7:03	7:01	7:00	6:58	6:57	6:55	6:54	6:52	6:51	6:50	6:48	6:47	6:45	6:44	6:42	6:41	6:40	6:38	6:37	6:35
Sunset (PM)	6:32	6:33	6:34	6:35	6:35	6:36	6:37	6:37	6:38	6:39	6:39	6:40	6:41	6:42	6:42	6:43	6:44	6:44	6:45	6:46	6:47	6:47	6:48	6:49	6:49	6:50	6:51	6:52	6:52	6:53

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	11.3	7:17	6:32
2	11.3	7:15	6:33
3	11.3	7:14	6:34
4	11.4	7:12	6:35
5	11.4	7:11	6:35
6	11.4	7:10	6:36
7	11.5	7:08	6:37
8	11.5	7:07	6:37
9	11.5	7:05	6:38
10	11.6	7:04	6:39
11	11.6	7:03	6:39
12	11.7	7:01	6:40
13	11.7	7:00	6:41
14	11.7	6:58	6:42
15	11.8	6:57	6:42
16	11.8	6:55	6:43
17	11.8	6:54	6:44
18	11.9	6:52	6:44
19	11.9	6:51	6:45
20	11.9	6:50	6:46
21	12.0	6:48	6:47
22	12.0	6:47	6:47
23	12.0	6:45	6:48
24	12.1	6:44	6:49
25	12.1	6:42	6:49
26	12.2	6:41	6:50
27	12.2	6:40	6:51
28	12.2	6:38	6:52
29	12.3	6:37	6:52
30	12.3	6:35	6:53

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.91 kWh/m².

For context, solar energy here swings from a low near 2.45 kWh/m² to a high of 6.64 kWh/m² in January across the year — September's 4.91 kWh/m² falls in the middle.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Solar energy (kWh/m²)	4.2	4.3	4.3	4.3	4.4	4.5	4.5	4.6	4.6	4.7	4.7	4.8	4.8	4.9	4.9	5.0	5.0	5.0	5.1	5.1	5.2	5.2	5.2	5.3	5.3	5.3	5.3	5.4	5.4	5.4
Level	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright

	Solar energy (kWh/m²)	Level
1	4.2	Bright
2	4.3	Bright
3	4.3	Bright
4	4.3	Bright
5	4.4	Bright
6	4.5	Bright
7	4.5	Bright
8	4.6	Bright
9	4.6	Bright
10	4.7	Bright
11	4.7	Bright
12	4.8	Bright
13	4.8	Bright
14	4.9	Bright
15	4.9	Bright
16	5.0	Bright
17	5.0	Bright
18	5.0	Bright
19	5.1	Bright
20	5.1	Bright
21	5.2	Bright
22	5.2	Bright
23	5.2	Bright
24	5.3	Bright
25	5.3	Bright
26	5.3	Bright
27	5.3	Bright
28	5.4	Bright
29	5.4	Bright
30	5.4	Bright

Planning a trip in September

Hazard calendar for Dee Why

In seasonPeak

None of Dee Why's seasonal hazards are active in September. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Dee Why sits in the South Indian Ocean cyclone belt; the season peaks January–March.

Cyclone

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Is September a good time to visit Dee Why?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

6.9

Sightseeing

3rd-best month of the year

2.9

Beach & pool

8th-best month of the year

September is a reasonable time to visit Dee Why for sightseeing.

What to pack for Dee Why in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Dee Why sees daytime highs around 19°C and nights near 13°C. Worth packing: sun protection. About 7 days see rain.

sun protection

Sea temperature near Dee Why in September

The nearest coast averages about 18°C in September — 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 September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 6 — enough to warrant sun protection. 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

Location & terrain

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.

3 km

170 m

artificial surfaces 34%

16 km

223 m

water 52%

80 km

811 m

trees 50%

treesgrasslandartificial surfacesbare terrainwater

← August Dee Why year-round climate October →Best places to visit in September

September weather nearby: Manly 5.0 km · Pittwater 10 km · Mosman 11 km · Chatswood 11 km · Saint Ives 12 km · Sydney Central Business District 15 km · Sydney 15 km · Surry Hills 16 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).

	Avg high (°C)	Avg low (°C)
1	18	12
2	18	12
3	18	12
4	18	13
5	18	13
6	18	13
7	18	13
8	18	13
9	18	13
10	18	13
11	19	13
12	19	13
13	19	13
14	19	13
15	19	13
16	19	13
17	19	13
18	19	13
19	19	13
20	19	14
21	19	14
22	19	14
23	19	14
24	20	14
25	20	14
26	20	14
27	20	14
28	20	14
29	20	14
30	20	14

	Clearer (%)	Cloudier (%)
1	74	26
2	74	26
3	74	26
4	74	26
5	75	25
6	76	24
7	76	24
8	76	24
9	76	24
10	77	23
11	77	23
12	77	23
13	77	23
14	78	22
15	78	22
16	78	22
17	76	24
18	76	24
19	76	24
20	76	24
21	76	24
22	76	24
23	75	25
24	74	26
25	74	26
26	73	27
27	73	27
28	72	28
29	72	28
30	71	29

	Rain chance (%)
1	26
2	26
3	26
4	26
5	26
6	26
7	25
8	25
9	24
10	24
11	23
12	23
13	23
14	22
15	22
16	21
17	21
18	21
19	21
20	21
21	20
22	20
23	20
24	20
25	20
26	21
27	21
28	21
29	22
30	22

	Dry (%)	Comfortable (%)	Humid (%)
1	91	9	0
2	91	9	0
3	90	10	0
4	90	10	0
5	90	10	0
6	90	10	0
7	90	10	0
8	90	10	0
9	90	10	0
10	90	10	0
11	89	11	0
12	89	11	0
13	88	11	1
14	87	12	1
15	86	13	1
16	86	13	1
17	85	14	1
18	84	15	1
19	83	15	2
20	82	16	2
21	82	16	2
22	81	17	2
23	80	17	3
24	79	18	3
25	79	18	3
26	78	19	3
27	76	20	4
28	75	21	4
29	74	22	4
30	74	22	4

	Avg high (°C)	Avg low (°C)
1	18	12
2	18	12
3	18	12
4	18	13
5	18	13
6	18	13
7	18	13
8	18	13
9	18	13
10	18	13
11	19	13
12	19	13
13	19	13
14	19	13
15	19	13
16	19	13
17	19	13
18	19	13
19	19	13
20	19	14
21	19	14
22	19	14
23	19	14
24	20	14
25	20	14
26	20	14
27	20	14
28	20	14
29	20	14
30	20	14

	Clearer (%)	Cloudier (%)
1	74	26
2	74	26
3	74	26
4	74	26
5	75	25
6	76	24
7	76	24
8	76	24
9	76	24
10	77	23
11	77	23
12	77	23
13	77	23
14	78	22
15	78	22
16	78	22
17	76	24
18	76	24
19	76	24
20	76	24
21	76	24
22	76	24
23	75	25
24	74	26
25	74	26
26	73	27
27	73	27
28	72	28
29	72	28
30	71	29

	Rain chance (%)
1	26
2	26
3	26
4	26
5	26
6	26
7	25
8	25
9	24
10	24
11	23
12	23
13	23
14	22
15	22
16	21
17	21
18	21
19	21
20	21
21	20
22	20
23	20
24	20
25	20
26	21
27	21
28	21
29	22
30	22

	Dry (%)	Comfortable (%)	Humid (%)
1	91	9	0
2	91	9	0
3	90	10	0
4	90	10	0
5	90	10	0
6	90	10	0
7	90	10	0
8	90	10	0
9	90	10	0
10	90	10	0
11	89	11	0
12	89	11	0
13	88	11	1
14	87	12	1
15	86	13	1
16	86	13	1
17	85	14	1
18	84	15	1
19	83	15	2
20	82	16	2
21	82	16	2
22	81	17	2
23	80	17	3
24	79	18	3
25	79	18	3
26	78	19	3
27	76	20	4
28	75	21	4
29	74	22	4
30	74	22	4

	Avg high (°C)	Avg low (°C)
1	18	12
2	18	12
3	18	12
4	18	13
5	18	13
6	18	13
7	18	13
8	18	13
9	18	13
10	18	13
11	19	13
12	19	13
13	19	13
14	19	13
15	19	13
16	19	13
17	19	13
18	19	13
19	19	13
20	19	14
21	19	14
22	19	14
23	19	14
24	20	14
25	20	14
26	20	14
27	20	14
28	20	14
29	20	14
30	20	14

	Clearer (%)	Cloudier (%)
1	74	26
2	74	26
3	74	26
4	74	26
5	75	25
6	76	24
7	76	24
8	76	24
9	76	24
10	77	23
11	77	23
12	77	23
13	77	23
14	78	22
15	78	22
16	78	22
17	76	24
18	76	24
19	76	24
20	76	24
21	76	24
22	76	24
23	75	25
24	74	26
25	74	26
26	73	27
27	73	27
28	72	28
29	72	28
30	71	29

	Rain chance (%)
1	26
2	26
3	26
4	26
5	26
6	26
7	25
8	25
9	24
10	24
11	23
12	23
13	23
14	22
15	22
16	21
17	21
18	21
19	21
20	21
21	20
22	20
23	20
24	20
25	20
26	21
27	21
28	21
29	22
30	22

	Dry (%)	Comfortable (%)	Humid (%)
1	91	9	0
2	91	9	0
3	90	10	0
4	90	10	0
5	90	10	0
6	90	10	0
7	90	10	0
8	90	10	0
9	90	10	0
10	90	10	0
11	89	11	0
12	89	11	0
13	88	11	1
14	87	12	1
15	86	13	1
16	86	13	1
17	85	14	1
18	84	15	1
19	83	15	2
20	82	16	2
21	82	16	2
22	81	17	2
23	80	17	3
24	79	18	3
25	79	18	3
26	78	19	3
27	76	20	4
28	75	21	4
29	74	22	4
30	74	22	4