How to Plan Events for Extreme Heat

Last week, a heatwave rolled across the UK and Europe and caught a lot of the events industry off guard. Sessions were cancelled. Schedules unravelled. For me, it had the same feeling as the early days of Covid: a shared realisation that almost nobody had planned for the thing that just happened.

That is what prompted this session. I invited two event safety specialists to talk through one simple shift in thinking. Heat is no longer an event you react to. It is a recurring condition you design for. We know it is coming, and we know it is coming more often. So the useful question is not “what do we do when it gets hot,” but “how do we build the event so heat is already handled.”

Holly Baker, a Safety, Site and Event Manager (TechIOSH) who works on festivals, stadiums and mass participation events, covered the outdoor side. Katie Hodson, a Health and Safety Consultant at First Option, a consultancy working across TV, film, corporate and experiential events, covered corporate events. Their settings differ, but the principles overlap far more than you might expect.

What “extreme heat event planning” actually means

Extreme heat event planning is the practice of building heat mitigation into an event from the design stage rather than adding it as a last-minute fix. It combines physical design (shade, airflow, ground surface), operations (hydration, queue management, scheduling), communication (briefings, signage, welfare checks) and emergency planning (medical provision, show-stop thresholds). As Holly put it, no single intervention keeps people safe. Layers do.

The goal is not only comfort. Heat stroke is dangerous, and in the worst cases it is fatal. Good heat planning reduces exposure, makes hydration effortless, and makes sure that if someone becomes unwell, it is spotted and treated fast.

Why heat has become a core planning challenge

This is not a one-off summer. In 2026, the UK’s Heat-Health Alert system, run by the UK Health Security Agency with the Met Office, issued red alerts covering multiple regions, the level that signals risk to life across the whole population, not just vulnerable groups. Alerts of that severity used to be rare. They are becoming routine.

For planners, that changes the maths. If a heatwave is a plausible condition for any summer event, then shade, water and welfare stop being “nice to have” and become part of the core spec, the same way you already plan for fire, crowds and power.

Start with shade

Shade is the single most effective thing you can do to reduce heat stress. Holly’s advice is to think about where people actually spend their time on site. It is rarely the middle of the crowd. It is the transitional spaces: queuing for entry, waiting at security, lining up for food, sitting down to eat. Those are the places to prioritise.

Her rule of thumb: nobody should ever be more than a few minutes’ walk from shade. Where you cannot move something into the shade, cover it instead. Cover the security queue so people are not feeling faint by the time they reach the front. Cover the first aid area, because you do not want someone being treated for heat stroke in an even hotter spot.

Holly has started using big tops and circus-style structures far more. They provide shade in heat and cover in rain, which matters in the UK. They are not cheap, but she has worked events where, without that cover, people would have left because of the discomfort, and the event would have suffered for it.

Build cooling zones people can find

A cooling zone is a dedicated, well-signposted space where people go to bring their body temperature down. Holly’s version includes a large shade structure, misting fans if the budget allows, plenty of cold drinking water, and somewhere to sit that is not the bare ground. She also stations a couple of first aiders nearby, not a full medical tent, but people who can recognise the signs of heat illness and act.

These zones do double duty. They become chill-out spaces, and if you drop an experiential pop-up inside one, you drive traffic to it while giving people a reason to cool down. They matter most for people who feel heat more strongly: young children at family events, older adults, people with disabilities and expectant mothers. Holly is running a festival aimed at the over-65s this summer, and is building in more of these zones precisely because susceptibility rises with age.

Make hydration effortless

Free water is a licensing requirement. The mistake is making people work for it. If getting water means queuing at the bar, asking, then queuing again, plenty of people simply will not bother.

Holly’s fix is hydration stations spread around the site. The Glastonbury model works well: sell a branded refillable bottle on arrival that people top up all day. You generally cannot ask people to bring their own water, because security cannot tell water from a clear spirit without opening every bottle, and mass bottle-checking creates longer, hotter queues. A workable middle ground is to allow one sealed bottle or an empty refillable, with a hydration station immediately inside the gate so people fill up the moment they are through the search. Reusable bottles also support your sustainability goals.

Katie added an important caution on electrolytes. They help replace salts, but you can overdo them, and too many can have the opposite effect. Build them in at sensible points, such as around meals, rather than encouraging people to sip them constantly. She also flagged appetite: people eat less in heat but still need energy, so smaller, more frequent meals or high-energy snacks like bananas, nuts and naturally hydrating fruit work better than three big sittings.

Design the ground and the airflow

The surface underfoot changes how hot a space feels. Tarmac radiates heat back up at you, so it always feels hotter than grass. Where you can, put people on grass or temporary decking. Both come with trade-offs: decking can harbour rats underneath, which brings a leptospirosis risk, and artificial turf is plastic, so it heats up just as much as hard ground while looking deceptively green.

Holly’s practical approach on a mixed site is to use hard, tarmacked areas for back of house, where trucks tip out and stages sit, and keep grass for the places people dwell, such as the pit or the main dancing area. Grass does not reflect heat, people can sit on it without burning, and it is easier on the legs over a long day.

Airflow is the other lever. Arrange structures to avoid enclosed spaces, narrow corridors and dead corners where hot air collects. Anyone who has stood in a sealed marquee with the back flaps down knows how quickly it becomes an oven. Where you can, line your openings with the prevailing wind, leave generous gaps between structures for ventilation, and take the sides off temporary structures when security allows.

Two more editorial-worthy details Holly mentioned: order lighter-coloured canopies and tents, because they absorb less heat, and keep generators well away from people, because of the heat they throw off.

Cut queue times and rethink the schedule

Long queues in direct sun make people ill before the event has even started. Holly’s toolkit here is straightforward: use multiple entry gates, invest in faster digital scanners, and spread food vendors across the site rather than clustering them into one food village where thousands end up baking in the same line. Shade every queue you can. Where you cannot, send a runner down the line with cups of water, asking if people are all right. It does not need to be a bottle each. Cups are fine.

Scheduling is a design tool too. Holly calls it the Spanish approach: start early, work hard from the cool part of the morning, break properly over the hottest hours, then resume when it eases. A proper break means real rest, not a sandwich eaten crouched behind a stage. Local noise limits can constrain this, especially in city stadiums where you cannot work before 8am or after 8pm, so it becomes a balancing act. Where the promoter will pay for a longer site tenancy, a slightly longer, safer build is worth it.

The same logic applies to the programme itself. Schedule physically demanding activities for early morning or evening. At a recent obstacle race, Holly’s team removed the competitive sprint from the middle of a twelve-kilometre course, so people were not running six kilometres and then sprinting flat out in peak heat. You cannot always strip out exertion, but it is worth asking where you can.

Protect your staff, not just your guests

Holly makes a point she repeats on every site: everyone on site is a person, including the crew back of house. Your staff, contractors and volunteers are often the most heat-exposed people there. They work longer hours, they wear PPE (and hi-vis vests do not breathe), and their work is physical, whether that is heavy manual labour or a safety officer walking the site all day.

So schedule breaks and make sure people take them. Provide a welfare area that is genuinely cool and covered, not a shipping container with a kettle in it. Supply water and electrolytes, because chugging plain water alone leaves people feeling worse, not better. And rotate people out of the sun. On a recent obstacle event in Leeds, Holly had enough volunteers to rotate everyone in and out every twenty minutes, and it transformed how they felt and how the event ran. Happy staff set the tone, and the crowd feels it.

Katie brought the corporate angle. Dress codes are a heat problem. Black absorbs and radiates heat, and corporate events default to it. Relax the code where you can: looser fabrics, smart shorts, white shirts instead of black. Let security take their jackets off, and brief them explicitly, because they will not assume they are allowed to. For talent in costumes or mascots, get them into costume at the last possible moment and build in more frequent breaks.

Build a safety culture that gives permission

Mitigations only work if the culture lets people use them. Katie shared a moment from a recent job that stuck with me. She noticed an event coordinator who had been on her feet for hours, told her there was a vehicle with air conditioning standing by, and suggested she take a break. The response: earlier in her career she had been taught that sitting down “looks bad,” so she kept going anyway, even though nobody on the current job expected that of her.

That is a culture problem, not a personal failing. A strong safety briefing at the start of the day should tell people plainly that taking a five-minute break is fine, that coming forward when they feel unwell is expected, and that nobody will frown at it. Because event managers are stretched thin, Katie recommends a dedicated welfare runner or coordinator whose only job is to move around the site offering water and checking that people have applied sunscreen. You forget, and by the time the headache and nausea arrive, you are already dehydrated. On sunscreen, she is firm: factor 50, and yes, you will still tan. Skin damage does not reverse. And if you are the client, you have a duty of care to provide sunscreen, water and PPE. Do not rely on freelancers and contractors to bring their own.

Know the signs of heat illness

Both speakers stressed this, and it belongs in your health and safety induction. Holly asks new crew if they know the three main signs before they start. The assumption is that a headache is the first flag. Often it is not.

Katie described a student steward standing in the shade who had not drunk enough all day. He had no headache and no nausea, but he was confused, disoriented, staring into the distance, tripping over his feet and clearly fatigued, and it was only midday. The medic was called and he was fine, but the early signs were behavioural, not the textbook ones people watch for.

Signs to brief your teams on, drawn from the session:

• Confusion or disorientation
• Dizziness
• Feeling sick or nauseous
• Unusual fatigue or stumbling
• Headache (common, but not always first)

Everyone has a different heat threshold. Some people last all day; others struggle within a couple of hours. So do not treat the crew as one block, and teach people to watch each other, not just themselves. For clinical detail on heat exhaustion and heat stroke, point your teams to NHS guidance.

Plan medical provision around risk, not minimums

Katie stressed this point. There is plenty of guidance out there: government advice, the Purple Guide, the Green Guide and more. But guidance gives you a baseline. Your first move should always be to risk assess the specific event, because that assessment may show you need more cover than the minimum suggests.

In extreme heat, both speakers favour more basic first aiders on the ground, people who can hand out ice packs and electrolytes, so the clinicians (doctors, paramedics, nurses) are freed up for the more serious cases. Roving medics who walk the site carrying water, advising people and directing them to the med tent take pressure off the main medical area and catch problems early. Their visibility alone prompts people to come forward who otherwise would have told themselves they would feel better in an hour.

A few more practical points:

• Have a backup medic. Medics get busy, they can become unwell themselves, and they are often outside and exposed.
• Understand exactly what your medic can and cannot do. Can they prescribe? What are the limits of their qualification level? Decide what you need before you book.
• Brief medics to walk the site, not just sit in the first aid post, so they spot things you will not.
• Consider a dedicated welfare provision alongside medical cover, even a single person focused purely on keeping people cool and hydrated.

One caution worth repeating: vet your medical suppliers as rigorously as any other contractor. Do not rely on their paperwork alone. Read their risk assessments, question anything that looks off, and familiarise yourself with what the badges and uniforms actually mean, so that what is promised on paper matches what turns up on site.

Decide your show-stop thresholds in advance

A show stop is the point at which you pause or end the event because conditions have become dangerous. Katie’s advice is to have that conversation early, and to accept that every event’s threshold is different. It depends on whether you are indoors or outdoors and on how many mitigations you can deploy. An event with air-conditioned welfare units can safely run longer than one without.

Agree in advance: at what stage does this become dangerous, and what extra mitigations can you introduce at, say, level two or three to avoid reaching a full stop at all. Underpinning all of it is monitoring. Watch live weather apps, and watch humidity, not just temperature. Cross-checking several apps and sources gives you the clearest picture of what is coming.

Check structures and ground conditions daily

Heat changes the ground your structures stand in. Katie described a mountain bike event where the earth became so dry that a large gantry’s stakes started to pull away, and it lost some of its structural stability. Dry ground is not the stable ground your build was signed off against.

Her advice: check ground conditions daily, and get a structural engineer or the structure provider to reinspect each morning on longer events. And trust your instincts. Standards differ abroad, and even a sign-off from a local competent person is not a reason to ignore something that looks wrong. Asking the question is part of the job.

Do not forget the opposite extreme: heavy rain

The same climate volatility that brings heatwaves brings sudden heavy rain, a point raised for events in Ireland and just as relevant across the world. Both speakers had a lot to add.

• Manage mud early. Vehicles, footfall and queuing create mud pits, so lay wood chip, matting or trackway. Holly prefers metal trackway over rubber, because rubber slides and you end up dragging layers of matting out of a bog.
• Handle flood water. Find flood-prone areas from the landowner, avoid building there, and fence them off if you cannot. Do not let people enter flood water, and be aware that cables running through wet ground raise a leptospirosis risk from animal waste washed into the water. Any small cut should be cleaned and seen by a medic.
• Watch structural stability in the wet too. Waterlogged earth can shift or sink, so heavy ballast needs a platform or base underneath rather than sitting straight on mud.
• Provide drying-off areas and hot drinks. Katie noted these are rarely provided and badly missed. Put weatherproof clothing (jackets, ponchos, boots) into your briefings for multi-day or all-day events.
• Site with drainage in mind, and back it all with a robust adverse weather plan, strong comms and good control-room logging.

Two field-tested tips: Holly uses the Met Office’s forecaster service in the UK, where for a small fee you can call and get a live forecast for your exact coordinates, not just the postcode, which is invaluable for electrical storms. And always check with the landowner before laying wood chip or straw, because some sites will not allow it. Her most memorable improvisation: cat litter behind the wheels of a telehandler for traction in the mud.

The six principles that carry across every event

The settings differ, but the same core principles ran through both talks. Use this as your baseline checklist for any summer event:

1. Design shade and cooling into transitional and dwell spaces. Nobody more than a few minutes from shade.
2. Make hydration effortless and impossible to miss. Stations over bar queues.
3. Protect your crew and build a culture that gives permission to rest. Everyone on site is a person.
4. Train everyone to spot heat illness early. Confusion and dizziness, not just headaches.
5. Set medical provision by risk assessment, not by minimum guidance. And vet your suppliers.
6. Monitor conditions and agree show-stop thresholds before the event. Humidity as well as temperature.

Pre-event heat readiness checklist

A practical audit to run against your next event plan:

• [ ] Shade mapped so no guest or crew member is far from cover
• [ ] Cooling zones designed, signposted and staffed with first aiders
• [ ] Hydration stations placed inside the gate and across the site
• [ ] Ground surfaces assigned: grass for dwell areas, hard standing for back of house
• [ ] Structures arranged for airflow, with lighter-coloured covers ordered
• [ ] Queue plan built for speed and shade, with water runners briefed
• [ ] Schedule shifted to cooler hours where noise limits allow
• [ ] Crew welfare area, rotation plan and electrolytes in place
• [ ] Dress code relaxed and briefed (corporate) or PPE welfare planned (outdoor)
• [ ] Heat illness signs covered in the health and safety induction
• [ ] Medical provision set by risk assessment, with a backup medic and vetted suppliers
• [ ] Show-stop thresholds agreed and weather and humidity monitoring set up
• [ ] Structural checks scheduled daily for longer builds
• [ ] Adverse weather (rain) plan ready as the flip side of the same volatility

The shift worth making

The old model treated extreme heat as bad luck. The new model treats it as a design input, the same as fire, crowd flow or power.None of the measures here are complex. Shade, water, breaks, briefings, monitoring. What changes outcomes is building them in from the first version of the plan, and layering them so that when the temperature climbs, the event holds.

If you take one thing from Holly and Katie, take this: it is never a single fix. It is many small, deliberate choices that add up to an event that stays comfortable, and stays safe, for everyone attending and everyone working it.

Your move: pull up your next summer event brief and run it against the six principles and the checklist above. If heat is not already written into the design, that is the gap to close now, while you still have time to plan rather than react. And if you want expert eyes on your specific event, Holly Baker and Katie Hodson both work directly with organisers on event safety.

I will keep publishing on event design and how to future-proof your events, so connect with me on LinkedIn, follow along on Instagram, or reach out through The MICE Blog to carry the conversation on. I would love your feedback I want to hear which topics you would like to learn more about next.