By Julia · weather-au.com editorial team · Published · 4 min read
Darwin has no spring and no autumn, only a Wet and a Dry. This article follows the year in the order Darwin lives it, from the dry season to the build-up, the monsoon and the long tail of the wet, using ten years of daily ERA5 data (2016 to 2025, Open-Meteo) and, for comparison, the site's 1991–2020 normals for Cairns and Broome. As ever, ERA5 is a reanalysis: a model on a 25 km grid, good for patterns and ranking, not a replacement for a rain gauge.
DarwinCairnsBroome
Normals 1991–2020 of the ERA5 reanalysis, as published on the city pages of this site.
June to September: the Dry
In the ten years, the average Darwin July receives 7 mm of rain and has 0.9 rain days (at least 1 mm). June has 7 mm, August 4 mm. Across June to August, a rainy day happens 3.2 times a year, in total. The longest stretch without a day of 1 mm in the series runs from 28 April to 29 September 2017: 155 days.
The temperature barely moves. Darwin's average maximum is 29.6 °C in July (the coolest month) and 30.4 °C in August; the average minimum is 21.2 °C in July. Nights can feel cool by local standards: the lowest minimum in ten years is 15.5 °C, on 18 July 2016. Cairns in the same months is milder still: normal maxima of 23 to 24 °C and minima of 18 to 19 °C, and Cairns keeps 24 to 28 mm of rain a month where Darwin keeps almost none. Broome, on the Kimberley coast, is almost dry from August to November in the normals: 2 mm in August, none in September, 4 mm in October.
October and November: the build-up
The rain is only beginning, and it is the hardest time of year to be outdoors. The maximum rises to 31.8 °C in October and 31.9 °C in November, and the nights stop cooling: the minimum is 26.0 °C in October and 26.5 °C in November. In an average year 24 nights in October and 27 in November have a minimum of 25 °C or more, against 29 in January: the nights are nearly as hot before the monsoon as during it.
Rain starts in earnest: 71 mm in October on average, 176 mm in November, with 13 and 18 rain days respectively. The guide to cyclones and the wet season gives the official dates of the cyclone season, 1 November to 30 April.
December to March: the monsoon
| Month | Rain (mm) | Normal 1991–2020 (mm) | Rain days (≥ 1 mm) | Daytime maximum (°C) | Night minimum (°C) |
|---|---|---|---|---|---|
| January | 459 | 436 | 26.8 | 30.3 | 26.3 |
| February | 360 | 383 | 22.0 | 30.1 | 26.2 |
| March | 250 | 289 | 24.6 | 30.5 | 26.1 |
| April | 98 | 100 | 12.8 | 31.4 | 25.5 |
| May | 18 | 14 | 3.4 | 31.2 | 23.9 |
| June | 7 | 2 | 1.4 | 30.1 | 22.1 |
| July | 7 | 2 | 0.9 | 29.6 | 21.2 |
| August | 4 | 2 | 0.9 | 30.4 | 22.1 |
| September | 32 | 16 | 7.5 | 31.1 | 24.2 |
| October | 71 | 74 | 13.4 | 31.8 | 26.0 |
| November | 176 | 176 | 17.8 | 31.9 | 26.5 |
| December | 301 | 330 | 22.0 | 31.5 | 26.6 |
Site normals 1991–2020 (ERA5 reanalysis) and Open-Meteo ERA5 archive 2016–2025; calculation by the editors.
The four wettest months of the ten years: January 459 mm, February 360 mm, December 301 mm and March 250 mm; January has 26.8 rain days out of 31. On average these four months bring 1,370 mm out of an annual 1,783 mm. Over the ten years, 92% of the rain falls between November and April.
The wet-season table shows how much a season can vary.
| Wet season | Rain, November to April (mm) | Days with 50 mm or more | First week with 100 mm or more, from 1 October | Rain, May to October after it (mm) |
|---|---|---|---|---|
| 2016–17 | 2 137 | 8 | 18 Dec 2016 | 83 |
| 2017–18 | 1 824 | 7 | 7 Jan 2018 | 83 |
| 2018–19 | 927 | 0 | 29 Dec 2018 | 71 |
| 2019–20 | 1 069 | 3 | 10 Jan 2020 | 169 |
| 2020–21 | 1 837 | 2 | 18 Dec 2020 | 124 |
| 2021–22 | 1 688 | 5 | 25 Dec 2021 | 241 |
| 2022–23 | 2 026 | 12 | 29 Nov 2022 | 81 |
| 2023–24 | 1 701 | 5 | 11 Jan 2024 | 143 |
| 2024–25 | 1 640 | 2 | 19 Jan 2025 | 123 |
Open-Meteo, ERA5 archive, 2016–2025 (reanalysis, not a weather station); calculation by the editors.
The first week of at least 100 mm after 1 October is a rough marker of when the monsoon really starts. It arrives as early as 29 November (the 2022–23 season) and as late as 19 January (2024–25 season), with 2017–18 and 2019–20 falling on 7 and 10 January. The seasons are as different as their start dates: 2,137 mm in 2016–17, but only 927 mm in 2018–19, and 1,069 mm in 2019–20. In 2018–19 no single day reaches 50 mm; in 2022–23 twelve do. The wet season of 2018–19 is 54% of the 1,714 mm which the 1991–2020 normals give for November to April.
The wettest single day in the series is the 22 November 2025: 227 mm, followed by 125 mm the next day. It is a reanalysis value for a grid cell, so treat it as an indication of order of magnitude, not as an official gauge reading.
April and May: the tail
April is the transition: 98 mm, 12.8 rain days. May drops to 18 mm and 3.4 days, with the maximum at 31.2 °C and the nights down to 23.9 °C. By June the rain days are 1.4 a month. Cairns lags a month behind Darwin: it still has 97 mm in April (normal) and 44 mm in May, with 13 and 10 rain days.
What it means for a trip
- May to September is the season for walking, camping and the national parks such as Kakadu and Litchfield. It is the one time of year when rain is a surprise.
- October and November are hot but quiet: expect 32 °C and nights above 25 °C.
- December to March is a different holiday: heavy rain and the cyclone season. Check the radar every day.
- Compare with Cairns: the Queensland tropics have a shorter and gentler dry season, with some rain in every month. If you want the reef and rainforest rather than the savanna, Cairns is wetter in the winter and cooler.
Numbers for other cities are in when to visit Australia; the other end of the heat-and-dryness story is told in fire-season weather.
Period of the data cited: 2016–2025.