Every winter the same question lands in group chats and site cabins: "Is it too cold to work?" Someone always claims there's a legal minimum temperature below which the site has to shut. There isn't — not for outdoor work, anyway. But that myth hides a real duty. Cold, wet, icy conditions change the risk profile of almost every task on site, and the law expects you to manage that. Get it wrong and you're looking at slips, trips, hypothermia, worsened hand-arm vibration injury and poor decision-making around plant and height.
Here's what actually applies, and the practical steps that keep a winter site running safely.
Is there a legal minimum working temperature?
Short answer: no fixed number for outdoor work. The Workplace (Health, Safety and Welfare) Regulations 1992 require a "reasonable" indoor temperature — HSE suggests at least 16°C for most indoor work, or 13°C where the work is physically demanding. But those figures apply to enclosed workplaces, not an open scaffold in January.
For outdoor and exposed work, your duty comes from the Management of Health and Safety at Work Regulations 1999 and the Health and Safety at Work etc. Act 1974: you must assess the risks and take reasonably practicable steps to control them. Cold is a hazard like any other — it goes in your risk assessment and you plan around it. If you've never captured it formally, our general library of task-specific risk assessments covers the activities most affected by weather, and the guide on whether you legally need a risk assessment explains the threshold in plain English.
The real risks cold weather adds to a site
Cold doesn't just make people uncomfortable — it multiplies existing hazards:
- Slips, trips and falls. Ice, frost, standing water and mud are the biggest winter injury cause. A frosted scaffold board or ladder rung turns a routine climb into a fall.
- Reduced dexterity and grip. Cold hands drop tools, fumble fixings and lose the fine control needed for safe work at height or with power tools.
- Worsened HAVS. Cold constricts blood vessels, so vibrating tools do more damage per trigger-minute in winter. If you already struggle with this, our breakdown of why HAVS monitoring fails on site is worth a read before the frost sets in.
- Hypothermia and cold stress. Prolonged exposure, especially when wet or windy, drops core temperature and impairs judgement long before anyone feels seriously unwell.
- Poor concentration. Shivering, numbness and the urge to rush to get indoors all raise the chance of a mistake around plant, excavations or live services.
- Frozen plant and materials. Hydraulics stiffen, concrete and mortar won't cure, and diesel can gel — all of which push people to improvise unsafely.
Practical controls for a winter site
None of this needs a consultant. It needs planning and a few sensible provisions written into your method of work. Build these into your RAMS rather than leaving them to chance — the RAMS & Permits library has editable method statement templates you can tailor with winter controls.
Before work starts each day:
- Walk the site and check access routes, scaffolds, ladders and working platforms for ice and frost before anyone uses them.
- Grit and clear pedestrian routes, ramps and steps — keep a stock of grit and a spreader on site.
- Check the forecast and plan the day around the worst of the weather; schedule exposed or height work for milder parts of the day where possible.
Protecting the crew:
- Provide suitable PPE: insulated, waterproof, breathable layers, thermal gloves that still allow grip, and non-slip footwear.
- Rotate tasks and build in warm-up breaks — a heated welfare cabin isn't a luxury, it's part of your welfare duty under CDM 2015.
- Keep hot drinks available and encourage regular warming breaks, especially for anyone using vibrating tools.
- Watch for cold stress signs — shivering, clumsiness, confusion, slurred speech — and treat them seriously.
Managing the work:
- Reassess work at height daily in icy conditions; a scaffold handover and inspection regime matters more than ever. Our scaffold risk assessment guide covers what good inspection looks like.
- Reduce manual handling in slippery conditions and reassess loads where footing is poor.
- Keep plant warm and serviced; don't let frozen hydraulics tempt anyone into workarounds.
Brief it to the crew. A five-minute toolbox talk at the start of a cold snap does more than any poster. Winter-relevant topics — slips and trips, working at height, HAVS, PPE and welfare — are all in the toolbox talks library, ready to deliver with an attendance record.
Don't forget welfare
Under CDM 2015 the principal contractor must provide adequate welfare facilities, and that includes somewhere warm to take breaks, dry clothing, hot drinks and a means to warm up. Cold weather sharpens the welfare duty — a damp, unheated cabin isn't good enough when the temperature drops. If you're unsure which documents your winter site needs, the free H&S Document Checker will point you to the right ones.
FAQ
Is there a legal maximum or minimum temperature to stop outdoor work?
No. There's no fixed outdoor temperature at which work must stop. Your duty is to assess the risk and apply reasonably practicable controls. For indoor workplaces, HSE suggests a minimum of around 16°C (or 13°C for strenuous work), but that doesn't apply to open sites.
Do I have to provide a heated welfare cabin?
Under CDM 2015 you must provide adequate welfare, including somewhere warm to rest and take breaks and a means of making hot drinks. In cold weather, heating that rest area is part of meeting that duty.
Does cold weather affect HAVS risk?
Yes. Cold reduces blood flow to the hands, which increases the damage caused by vibrating tools. Keep hands warm, provide warm-up breaks and manage trigger-time more tightly in winter.
Should I write cold weather into my risk assessments?
Yes. Treat cold, ice, wind and wet as hazards in the relevant task risk assessments and method statements, with specific controls for slips, access, PPE and welfare. Review them when a cold snap is forecast.
Keep your winter site covered
Cold weather doesn't need a special document set — it needs your existing RAMS, risk assessments and toolbox talks updated with sensible winter controls and briefed to the crew. The Risk Assessment Library Bundle gives you all 58 task-specific assessments to tailor, or go unlimited with SafetyPod Membership at £69/year and pull any template you need through the winter and beyond. Written by a NEBOSH-qualified team, fully editable, instant download — so you can plan the cold out of the job before it costs you a fall.