Your January weather guide
HotWeather in Sydney in January
January is a good time to visit Sydney if you want warm days and a sea you can swim in, but not if guaranteed dry weather is your priority. Average highs are 25.7°C, nights average 19.5°C and the sea is around 22.5°C. For a UK traveller, that means a clear shift into summer clothing, with a light layer for cooler evenings. The catch is rain and humidity, so keep outdoor plans flexible rather than expecting uninterrupted sunshine.
Long-term climate averages for Sydney, not a forecast · 1991-2020
Sydney, month by month
Your snapshot
At a glance
The useful details for Sydney.
- Average daytime high
- 25.7°C
- 9 in 10 days stay below 30°C
- Average night-time low
- 19.5°C
- coldest 10% of nights: 17°C or lower
- Compared with London
- +18.3°C
- London averages 7.4°C in January
- Sea temperature
- 22.5°C
- year to year: 22°C to 23°C
- Sunshine per day (est.)
- 6.3h
- 45% of 14.0 h of daylight
- Rainy days (1 mm+)
- 9
- 68 mm over the month
- Humidity
- 73%
- Days over 25°C
- 53%
- 11% over 30°C
- Record high 1991-2020
- 42.0°C
- 2020-01-04
- Record low 1991-2020
- 12.6°C
- 2018-01-18
- Flight from London
- ≈ 22 h
- 17017 km, long-haul (estimate for a direct flight)
Records are observed extremes within 1991-2020, not typical holiday conditions. Warm-day percentages are shares of days, not day counts.
How January compares
January is the 1st warmest month of the year in Sydney and ranks 32nd of 134 destinations we compare for January - see where else is hot in January. Against London's average high of 7.4°C in January, Sydney is 18.3°C warmer by day and 17.3°C warmer at night.
Daytime and night-time in January
The typical January day in Sydney peaks at 25.7°C, but that is an average: the warmest 10% of days reach 30.3°C or more. About 53% of days top 25°C and 1 in 9 pass 30°C. Nights average 19.5°C; one night in ten drops to 17.1°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest January day here reached 42.0°C (2020-01-04) and the coldest night 12.6°C (2018-01-18).
Rain in January
Wet (more than 8 rainy days): about 9 days with 1 mm or more, 68 mm in total. Year to year it varies a lot - the wettest January was 2016 with 199 mm, the driest 2009 with 8 mm. Humidity averages 73%.
Sea temperature in January
The sea averages 22.5°C - warm enough to swim (22°c+). Depending on the year it ranges from 21.7°C to 23.2°C. For the warmest sea here, come in February (23.0°C).
Sunshine and daylight
Around 6.3 hours of sunshine a day (estimated from cloud cover), 14.0 hours of daylight: the sun rises about 05:59 and sets about 20:09 local time in mid-January. Average cloud cover is 55%.
Is January a good time to visit Sydney?
Yes - it is one of the better months: hot days, manageable rain. The best months for Sydney on our scoring are December, January, February; months averaging 25°C or more: Jan, Feb.
Summer warmth, with some hotter days
January is Sydney's warmest month, but that does not mean every afternoon brings intense heat. Days reach 30°C on 11% of occasions, so plan for occasional hotter spells rather than treating them as the norm. Compared with London's January high of 7.4°C, the change will feel substantial. Humidity averages 73%, which can make warm weather feel sticky, especially when walking around at midday. Choose loose, breathable clothes and leave room for shade breaks; on hotter days, shift longer walks towards morning or later afternoon. Evenings are generally mild, though a light jumper is sensible if you tend to feel the cold.
Allow for rain, not just sunshine
Rain is a meaningful part of the January picture: about 9 days have measurable rainfall. That is enough to make a rigid outdoor itinerary a gamble, but it does not tell you that those days will be washouts. Keep an indoor alternative in mind and carry a light waterproof rather than packing only for the beach. There are about 14 hours of daylight, yet sunshine averages 6.3 hours, so long days should not be confused with consistently clear skies. The practical advantage is flexibility: you have daylight to move plans around, while cloudier periods need not stop you spending time outdoors if it stays dry.
A little perspective
Sydney through the year
January is highlighted. See how it compares with the rest of the year.
| Month | Day | Night | Sea | Sun/day | Rain mm | Rainy days | Days 25°C+ |
|---|---|---|---|---|---|---|---|
| JanuarySelectedbest | 25.7°C | 19.5°C | 22.5°C | 6.3 | 68 | 9 | 53% |
| Februarybest | 25.1°C | 19.5°C | 23.0°C | 5.7 | 87 | 11 | 47% |
| March | 23.8°C | 18.1°C | 22.7°C | 5.9 | 70 | 11 | 29% |
| April | 21.6°C | 15.2°C | 21.9°C | 6.0 | 54 | 8 | 10% |
| May | 18.9°C | 12.2°C | 20.6°C | 5.8 | 46 | 7 | 1% |
| June | 16.5°C | 10.2°C | 19.1°C | 5.4 | 65 | 8 | 0% |
| July | 16.0°C | 8.9°C | 18.0°C | 6.4 | 36 | 6 | 0% |
| August | 17.2°C | 9.2°C | 17.5°C | 7.3 | 37 | 5 | 1% |
| September | 19.6°C | 11.4°C | 17.7°C | 7.4 | 40 | 6 | 7% |
| October | 21.5°C | 13.7°C | 18.6°C | 6.7 | 51 | 8 | 18% |
| November | 22.7°C | 15.7°C | 19.6°C | 6.0 | 70 | 9 | 24% |
| Decemberbest | 24.4°C | 17.7°C | 21.0°C | 6.3 | 56 | 9 | 39% |
Day = average daytime high, night = average night-time low, 1991-2020.Sun is hours per day; rainy days count 1 mm or more.
Day, night and sea
Monthly average temperatures, 1991-2020
- Day
- Night
- Sea
Best months here
On warmth, low rainfall and sunshine, start with these.
Keep exploring
Similar in January
Closest matches on daytime temperature, sea temperature and sunshine, in other countries.
A little more detail
Sydney in January FAQs
Plain answers, grounded in the averages.
Is Sydney hot in January?
Sydney is hot in January: the average daytime high is 25.7°C and nights average 19.5°C. About 53% of January days reach 25°C or more.
Can you swim in the sea in Sydney in January?
The sea around Sydney averages 22.5°C in January, which is warm enough for most people to swim comfortably. Between 1991 and 2020 it ranged from 22°C to 23°C depending on the year.
How much does it rain in Sydney in January?
Sydney sees about 9 rainy days (1 mm or more) and 68 mm of rain in a typical January. The wettest January between 1991 and 2020 was 2016 (199 mm) and the driest was 2009 (8 mm).
How sunny is Sydney in January?
Sydney gets around 6.3 hours of sunshine a day in January out of 14.0 hours of daylight (estimated from average cloud cover).
How does Sydney compare with the UK in January?
Sydney is on average 18.3°C warmer than London by day in January (25.7°C against 7.4°C).
What is the hottest January on record in Sydney?
Between 1991 and 2020 the hottest January day in Sydney reached 42.0°C on 2020-01-04, and the coldest night dropped to 12.6°C on 2018-01-18.
Is the sea warm enough to swim in January?
Yes. The sea averages 22.5°C, with a year-to-year range of 22°C to 23°C, making January suitable for swimming on temperature grounds. It may still feel cool as you get in, but this is not a cold-water month.
Is January a good choice given the long flight from London?
January is among Sydney's best months for weather, alongside December and February. The flight from London takes about 22 hours, so the trade-off is substantial travel time for summer warmth and swimmable seas, without a guarantee of dry days.
About these averages
ERA5-Land climate reanalysis via Open-Meteo (11 km grid) and NOAA Coral Reef Watch 5 km sea temperatures, 1991-2020
Averages computed from daily values at Sydney. Sea temperature from the nearest 5 km sea cell, 1.8 km from that point. Sunshine hours are estimated from average cloud cover.Records are the highest and lowest daily values in that 30-year period, not all-time records. These are climate averages, not a forecast for your trip. How we measure holiday weather
- Hot · 25°C+
- Warm · 20°C to below 25°C
- Mild · 15°C to below 20°C
- Cool · below 15°C