Field notes › Compliance
Summer on site: rostering with the heat in mind
Rostering for working in heat means deciding who is outside, when, for how long and how they get home, in a way that makes the site's heat controls easy to follow. For most labour hire crews that comes down to earlier starts, enough ticketed people on a shift to rotate the exposed work, new starts kept off the hardest jobs until they've adjusted, and a hard look at travel after hot shifts. Stop-work rules come from the site's procedure and your WHS regulator, not the roster.
What the regulators say about working in heat
Safe Work Australia's working in heat page is the national starting point. Its frequently asked questions say, as at September 2026, that there is no single maximum temperature at which work must stop, because humidity, air flow, how hard and long the work is and whether workers are acclimatised all change the risk. Scheduling work to cooler parts of the day is on its list of controls, and that one is a roster decision.
The states and territories enforce the laws and publish their own material. WorkSafe WA lists rescheduling hot tasks to the cooler part of the day, job or task rotation and arranging for more workers to do the job. WorkSafe Victoria says no maximum temperature for stopping work is set under Victoria's occupational health and safety act or regulations, though some workplaces have their own policy. SafeWork NSW sets out managing extreme heat as a risk, with workers and their health and safety representatives consulted at each step.
In the ACT, the code of practice for managing the risks associated with extreme temperatures took effect on 14 November 2025, so as at September 2026 the coming summer is its first full one. WorkSafe ACT's guidance says information and training must be provided to all workers, and names casual, shift and labour-hire workers and contractors. If you supply crews in Canberra, read the code before the first hot week.
Start with the site's own heat plan
Most sites that deal with serious summer heat have a heat management plan of some kind, covering when work stops or changes, how drinks and rest breaks are handled and who makes the call. Before summer, get a copy for every site you supply and read it with the roster in front of you. If a site doesn't have one, raise it with the client. It isn't a gap for your rosterer to fill with guesses, and nobody should take thresholds from a blog.
Earlier starts change more than the start time
Pulling the day shift earlier to finish before the worst of the afternoon is one of the most common summer adjustments, and it's usually a sensible one. It also moves everything attached to the shift. Crew who slept reasonably before a later start are now up well before dawn, and Safe Work Australia's FAQ notes that warmer nights during a heatwave can reduce sleep quality as well. Buses and camp meal times might not move with you, and a finish that used to line up with the ride home may now leave people waiting around in the heat.
When a client brings starts forward, tell the crew directly and in writing, rather than letting it travel by word of mouth from the site. Then check the knock-on effects before the first early shift, not after a week of people turning up tired.
Rotate the exposed work, and roster for it
Rotating people off the hottest tasks is usually a supervisor's call on the day, but it only works if the crew has enough people who can do each task. If one person on the shift holds the ticket for the job in full sun, there's nobody to swap in, and they end up doing it all afternoon.
So build summer crews with rotation in mind. For the exposed work, try to have at least two people on the shift who can do it. That might mean one more ticketed operator than you'd send in winter. When you're building the shift in Mustr, the crew panel shows each person's role and verified competencies, which makes it easier to see whether the crew you've pencilled in can actually swap around.
New starts haven't acclimatised yet
Safe Work Australia lists workers who aren't acclimatised, or who are returning after being away for a week or more, among those at higher risk of heat-related illness. WorkSafe WA's guidance says acclimatisation can take seven to 14 days, is reduced after three days away from hot work and is entirely lost after four weeks away. Safe Work Australia adds that it's different for every person and shouldn't be relied on as a control.
For the roster, anyone new to a hot site, or back from a break somewhere cooler, hasn't adjusted yet. Where you can, keep them off the most exposed role in the hottest stretch and tell their supervisor they're new. Make sure they've seen your heat guidance before the first shift, not after lunch on day one. In Mustr, onboarding can include a custom step to read and acknowledge a document, which is one way to be sure every worker has read it. It doesn't replace the site induction or someone keeping an eye on people on the day.
The drive home after a hot shift
The risk doesn't end when the shift does. A worker who has spent a long day in the heat and then drives home, back to camp or out to the airport is doing it tired and possibly dehydrated. For drive-in work, the roster decides how long that drive is and what time of day it happens. A last shift followed by a long drive deserves a second look, and so does a swing that finishes and heads straight onto the road. The fatigue side of this sits with the site's fatigue plan, and there's more on whose fatigue plan applies to labour hire crews.
Questions people ask
Is there a maximum temperature for working outside in Australia?
Safe Work Australia says there is no single stop-work temperature, because humidity, air flow, the work itself and acclimatisation all change the risk. WorkSafe Victoria says no maximum temperature is set under Victoria's occupational health and safety laws, though some workplaces have their own policy. Check the site's heat plan for any stop-work parameters agreed there.
How long does it take to acclimatise to working in heat?
WorkSafe WA's guidance says acclimatisation can take seven to 14 days, is reduced after three days away from hot work and is lost after four weeks away. Safe Work Australia says it differs for every person and shouldn't be relied on as a control. For rostering, treat anyone new to a hot site or back from a break as not yet adjusted.
What should change on the roster during a heatwave?
Safe Work Australia's heatwave controls include scheduling work to cooler parts of the day, reducing physical effort and not having workers work alone where possible. On the roster that can mean earlier starts, enough people on each shift to rotate tasks and nobody sent out solo. The site's heat plan decides what happens on the day.
Does the ACT have a code of practice for extreme temperatures?
Yes. The ACT Legislation Register lists the Work Health and Safety (Managing the Risks Associated with Extreme Temperatures Code of Practice) Approval 2025, which took effect on 14 November 2025 and was in force as at September 2026. WorkSafe ACT describes the code as practical guidance on managing the risks associated with extreme temperatures.
If you want to see how crews, tickets and travel sit together on one roster before summer arrives, try it with sample data.