Lumen Sites for mine & construction sites

North West Queensland weather for site work

Mount Isa and Cloncurry sit at the centre of one of Australia’s major base metals regions, mining copper, lead, zinc and silver. The climate is simple and harsh: a long, very hot dry season, a short wet season that brings most of the year’s rain in a few months, and heat stress for half the year.

The year at a glance

From December to March the region gets 77–81% of its rain, about 490–520 mm a year in all, while August averages only 2–3 mm. December is the hottest month, averaging 38° in Mount Isa and 39° in Cloncurry. Winter days are warm and dry, and July nights average 9–11°.

Averages for 1995–2024 from SILO (Queensland Government, CC BY 4.0), interpolated from Bureau of Meteorology observations. Heat-stress days: estimated WBGT reaching 28°, the caution level Lumen Sites starts with. Select a town for its month-by-month figures.
Town	January high	July low	Rain a year (mm)	Wettest month	Days reaching 40°	Heat-stress days
Mount Isa	36°	9°	488	Jan 126 mm	24	168
Cloncurry	37°	11°	519	Jan 140 mm	39	193

Heat

Heat-stress days by month

Average heat-stress days a month, 1995–2024: days when the estimated wet bulb globe temperature (WBGT) at the day’s peak reaches 28°, the caution level Lumen Sites starts with. From SILO (Queensland Government, CC BY 4.0), interpolated from Bureau of Meteorology observations.
Town	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Mount Isa	30	26	26	11	2	<1	<1	1	6	15	23	28
Cloncurry	31	27	29	17	4	1	1	2	8	20	26	30

Mount Isa averages 133 days a year reaching 35° and 24 reaching 40°; Cloncurry 159 and 39. Heat-stress days run at 168 a year in Mount Isa and 193 in Cloncurry, 81 and 102 of them at the stop level, and in December and January almost every day reaches the caution level. The hardest time is the build-up in November and December, when the heat peaks and the humidity rises ahead of the rain.

These figures use the Bureau of Meteorology’s simplified formula, which assumes moderate sun and light wind, so read them as how often heat needs managing. The WBGT calculator shows how quickly rising humidity lifts the estimate.

The wet season

The wet season is short and intense. Monsoon lows and storms can bring a month’s rain in a day, and on hard, dry ground it runs off fast: creeks rise within hours, causeways go under and haul roads close. A slow-moving monsoon low can flood the whole region, as the one in February 2019 did, cutting highways and isolating towns for days. See rain, the wet season and haul roads.

Storms and lightning

Thunderstorms are most frequent from October to March, often building through the afternoon, and bring lightning, strong gusts and dust ahead of the rain. Lightning detection matters here because thunder is easy to miss over plant noise: see lightning stand-down alerts.

Planning a year on site

Put shutdowns and big outdoor jobs into May to September, the dry, cooler months.
Stock fuel, parts and supplies before Christmas, in case roads are cut in the wet.
Run heat stress plans from October to March, and give new crews time to get used to the heat.
Check drainage, causeways and pit pumps before the first storms.