Beating the heat: what employers need to know about summer and workplace wellbeing
Summers are getting hotter across much of the world, and heatwaves are becoming more frequent and more intense. For most of us, that used to mean a few uncomfortable days in the office. Increasingly, though, the evidence shows that heat is a genuine workplace wellbeing issue, not just a comfort one.
It also shows up in the numbers. Recent survey data found that almost two thirds of office workers regularly feel too hot or too cold at work, more than half have argued with a colleague over the thermostat, and nearly one in ten have considered leaving their job over office temperature alone.
The 2025 WHO and World Meteorological Organization report on workplace heat found that worker productivity drops by around 2 to 3% for every degree above 20°C, and a 2026 review in Current Environmental Health Reports linked heat exposure to reduced cognitive performance more broadly.
Desk-based roles are lower risk than physically demanding outdoor jobs, but they are not risk-free. Concentration and decision-making can be affected well before anyone is close to heat exhaustion, and some colleagues, including older workers and those with existing health conditions, will feel it sooner than others. When discomfort is common enough to affect focus, morale and even retention, it stops being a minor irritation and becomes a genuine people risk.
Getting the office environment right
For office-based teams, the practical challenge is less about extreme heat and more about maintaining a comfortable, stable environment. Regardless of jurisdiction, most employers have some duty of care to ensure reasonable comfort indoors, and this applies to sedentary, desk-based roles just as much as physically demanding ones.
Research points to a sweet spot for office temperature, generally around 22°C, where cognitive performance and accuracy peak. Move much above that and response times slow and error rates creep up. That said, this is not a hard and fast rule. Perception of heat varies from person to person, depending on factors like clothing, activity level and individual physiology, so a single office-wide setting will always suit some people better than others.
Ventilation and air conditioning are the obvious starting points, but they need to be used thoughtfully. A stuffy, overheated office will affect focus and mood, but an office that is over-cooled can be just as disruptive, causing discomfort, headaches and the now-familiar office debate over the thermostat. The aim is a stable, moderate temperature rather than swinging between too hot and too cold, with some flexibility for individual comfort.
Simple, low-cost measures can make a real difference: closing blinds to reduce solar gain, moving desks out of direct sunlight, providing fans where air conditioning is not available, and encouraging regular breaks and hydration. International guidance, including the 2025 WHO and World Meteorological Organization report, also points to flexible working arrangements, such as adjusted hours or remote working on the hottest days, as effective ways to protect both wellbeing and performance when home environments are cooler than the office.
The commute matters too
Wellbeing during a heatwave does not start and end at the office door. For many employees, the commute is the most uncomfortable part of the day, particularly on crowded, poorly ventilated public transport or when cycling or walking in high temperatures. Heat-related fatigue, dizziness and dehydration during the commute can carry through into the working day, affecting concentration and mood long before anyone sits down at their desk.
Employers have a role to play here too, even though the commute itself is outside their direct control. Flexible start and finish times to avoid peak heat, encouraging employees to carry water, and simply acknowledging that a difficult commute is a legitimate wellbeing factor can go a long way. Where remote working is an option, allowing it on the hottest days removes commuting-related heat exposure altogether.
The bottom line
Heatwaves are becoming a regular feature of working life around the world, and the trend points in one direction. Heat affects wellbeing, concentration and performance in office-based roles, not just physically demanding outdoor jobs, and that impact will only grow as extreme heat becomes more common. Employers who treat indoor comfort as a core part of their wellbeing strategy now, rather than a seasonal afterthought, and who extend that thinking to the commute, will be far better placed to protect their teams as this shifts from an occasional challenge to a permanent feature of working life.
References
- World Health Organization & World Meteorological Organization (2025). Climate change and workplace heat stress: technical report and guidance. Geneva: WHO. ISBN 978-92-4-009981-4 (electronic), 978-92-4-009982-1 (print); WMO ISBN 978-92-63-11376-4.
- Nath A, Sahu S, Lee JKW. An umbrella review of systematic reviews and meta-analyses on occupational heat exposure, health risks and productivity losses globally. Current Environmental Health Reports, 2026;13(1):2.
- Guo X, Nkwopara C, Peters CE, Villeneuve PJ, McLeod CB. Impact of heat exposure on workers' health and safety: a scoping review. Occupational and Environmental Medicine, 2026;82(11):563-570.
- Cao B et al. Meta‑analysis of 35 studies examining the effect of indoor temperature on office work performance. Building and Environment, 2021; 203: 108089.
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