Lumen Sites for mine & construction sites

Goldfields and Murchison weather for site work

The Goldfields and Murchison are Western Australia’s gold and nickel country, from Kalgoorlie’s Golden Mile to the mines around Leonora, Laverton, Meekatharra and Cue. Summers are hot and dry, winter nights are cold, and the little rain there is can turn up in any month.

The year at a glance

Summer heat builds from November to March, and the further north you go the hotter it gets: January averages 34° in Kalgoorlie but 39° in Wiluna, Meekatharra and Cue. Winter days are mild and the nights cold, with July lows of 4–8°. Rain is low everywhere, about 245–325 mm a year, and in most towns it is spread across the year, with summer storms and tropical lows in the north and winter cold fronts in the south.

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
Kalgoorlie	34°	6°	275	Feb 41 mm	11	56
Kambalda	34°	5°	280	Jan 43 mm	10	59
Coolgardie	34°	5°	275	Feb 38 mm	10	54
Leonora	37°	6°	257	Feb 46 mm	24	89
Laverton	36°	6°	287	Feb 52 mm	18	78
Norseman	32°	5°	309	Jan 34 mm	6	51
Southern Cross	35°	4°	325	Jul 40 mm	10	67
Wiluna	39°	6°	312	Feb 53 mm	36	128
Cue	39°	7°	244	Mar 35 mm	35	115
Meekatharra	39°	8°	247	Feb 44 mm	35	114
Mount Magnet	38°	7°	255	Feb 41 mm	30	105

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	Aug	Sep	Oct	Nov	Dec
Kalgoorlie	17	14	8	1	0	0	<1	1	5	11
Kambalda	17	14	8	1	0	0	<1	1	5	12
Coolgardie	16	13	7	1	0	0	0	1	5	10
Leonora	23	19	13	3	<1	0	<1	3	10	17
Laverton	21	17	11	2	<1	0	0	3	8	15
Norseman	15	13	7	1	0	0	<1	1	4	10
Southern Cross	19	17	10	1	<1	0	<1	1	5	13
Wiluna	28	25	20	7	1	<1	1	8	15	24
Cue	28	25	20	5	<1	0	<1	4	12	22
Meekatharra	28	25	19	4	0	0	<1	3	12	22
Mount Magnet	27	24	18	4	<1	0	<1	3	10	20

The heat here is dry, so it shows in the thermometer more than in heat stress. Kalgoorlie averages 46 days a year reaching 35° and 11 reaching 40°, with 56 heat-stress days, nearly all of them from November to March. In the Murchison it is about double: Meekatharra averages 108 days reaching 35°, 35 reaching 40° and 114 heat-stress days.

Dry heat still catches people out. Sweat evaporates so quickly that it is easy to underestimate how much water is being lost, so hydration needs as much attention as the temperature. The WBGT calculator shows how the estimate moves with humidity, and heat stress forecasts cover planning the day around it.

Rain and storms

Summer storms bring lightning, gusty winds and short, heavy downpours, and the remains of tropical cyclones and monsoon lows can drop a month’s rain or more in a day or two. That summer rain matters most in the north, where around 60% of Wiluna’s and Meekatharra’s rain falls from December to March. In the south, winter cold fronts bring more of it: Southern Cross’s wettest month is July.

Heavy falls on hard, dry ground run off fast. Creeks rise quickly, salt lakes fill, and unsealed roads can close until they dry out. More in rain, the wet season and haul roads.

Cold nights, inversions and blasting

Clear, still winter nights are cold, with July lows averaging 4–8° and frost possible, and they set up strong temperature inversions in pits and low ground. A blast fired before the inversion breaks can carry airblast further and hold fumes close to the ground, so winter blasts are best timed for late morning or later. See blasting and temperature inversions.

Planning a year on site

Move heavy outdoor work and shutdowns away from December to February where you can, when heat stress peaks.
Plan for summer storms: lightning stand-downs, and roads that close at short notice after heavy falls.
In winter, time blasts for after the morning inversion breaks, and allow for frost at dawn.
New starters and fly-in fly-out crews arriving from Perth in summer need time to get used to the heat: Meekatharra’s January averages 39° against Perth’s 31°.