How To Keep Employees Safe In Hot Weather

General Safety By Matthew Coombes

Hot weather can significantly impact the general experience of working, and increase the risk of injury and ill health for workers. When we get hot, we get dehydrated or uncomfortable which can be distracting, and a distracted worker can cause or be involved in an accident.

When you’re considering heat in the UK, the consideration is how hot the temperature is relative to the environment, as opposed to relative to the world. There are many countries who regularly work in temperatures above 40*c+, but they’re much better prepared to do so, with supporting work policies, legislation and procedures. On the other hand, a roofer working in 40⁰C heat in the West Midlands, (where the average high temperatures for June, July and August are 19⁰C, 22⁰C and 21⁰C respectively) would be likely to be poorly equipped for the environment.

There is plenty of information available online about addressing the issues of extreme heat and cold in the workplace, and we have ourselves in the past written about what the temperature in the workplace should be.

However, something that often gets overlooked when it comes to issues with hot weather is the cause of the hot weather itself, the solar radiation.

Electromagnetic radiation given off by the sun travels a long way to get to you, around 150,000,000 kilometres. Radiation travels in straight lines, so when it reaches earth, the visible and invisible portions of the electromagnetic radiation are blocked by the nearest solid object. Cloud cover can reduce the amount of radiation that gets through, but it won’t block all of the radiation, so even on a cloudy day, most of the radiation from the sun is reaching the ground.

Dense structures like trees and buildings are able to ‘block’ much of the visible and invisible electromagnetic radiation. This ‘blocking’ of the visible waves, is how we see shadows; the visible light has been blocked from entering that space, so it appears darker.

The light that we can’t see is Ultraviolet Light or ‘UV’. UV light is on a spectrum that is invisible to the human eye. However, it is UVA and UVB light which causes significant damage to our skin. Both UVA and UVB penetrate our skin, causing genetic damage to the cells in our skin, which can lead to the development of skin cancers.

This is why when there is a high amount of solar radiation, it’s typically best to stand in the shade.

Where to get information on UV levels

If you’re in the UK, the Met Office website is the easiest way to find information on UV levels. You punch in the postcode that you will be working in and the forecast provides a prediction of the UV levels that are expected for each hour of the day. This is done with a 0 – 11 scale, with 0 meaning that there is no significant UV, and 11 meaning that UV levels are extreme. Moderate to high UV levels are where you are likely to experience sunburn and the forecast will show this with a colour and a number. Right now, the forecast for my area is indicating that today is the day this week with the highest UV, with a prolonged period of 5’s and 6’s throughout mid-day and levels not reaching low until around 6pm.

Controlling exposure to UV

Schedule work for lower UV hours

One of the simplest ways to reduce exposure to UV rays is to work when UV rays are at their lowest. This is when the part of the earth that you’re working in is in less direct sunlight, i.e., mornings and evenings.

By scheduling work for when UV is at it’s lowest, you’re substantially reducing the risk. This could mean a split day, working from 8:30 to 11:30, then resuming work when UV goes back down around 14:00 or 15:00.

The hours in which work can take place differ slightly between councils, so you will have to consider your local council rules and guidelines for making noise while working.

Staffordshire Council Newcastle Council Manchester Council
8:00 – 18:00 Monday to Friday 8:00 – 18:00 Monday to Friday 7:30 – 18:00 Monday to Friday
8:00 – 13:00 Saturday 8:00 – 13:00 Saturday 8:30 – 14:00 Saturday
No noisy works Sunday No noisy works Sunday No noisy works Sunday

The UK’s NHS recommends spending time in the shade between 11am and 3pm from March to October.

Keep covered / shaded

Where possible, ensure that you’re as covered as you can comfortably be, with as much skin covered as possible. This can provide a valuable barrier between your skin and solar radiation.

Where possible, set up shade that will be suitable for fully covering the work area, and consider how much time will be spent outside of the shade, travelling around the site, and moving materials.

It may be that you need to purchase new work wear that’s well suited for hot weather, such as lightweight hats that cover your neck, or breathable long-sleeved tops.


Sunscreen with a high UVA and UVB rating applied regularly to any exposed skin can reduce the chances of your skin becoming damaged, but sunscreen can easily be rubbed off, sweated off, or forgotten about and not applied regularly enough to be fully effective.

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