🔥 The European Heatwave of 2025: Time to Rethink "Normal" in Construction Contracts?

As Europe swelters under yet another record-breaking heatwave, with temperatures exceeding 30°C & peaking at 35°C for much of June, the question construction professionals should be asking isn't "How do we keep going?"—but rather, "Are our contracts and frameworks fit for this new climate reality?"

Having worked across jurisdictions, I'm often struck by how different countries embed (or neglect) weather risk in their legal and operational frameworks. Comparing the UK and Australia, especially this June and looking back at heatwaves in the past, has been particularly illuminating.

🌡️ June Over 30°C — Now the Norm, Not the Exception

In the UK, we once treated a 30°C day as a meteorological anomaly—good for the tabloids, bad for the trains. But in the past decade, Met Office records show June days breaching that threshold are now routine. In 2025, we’ve seen multiple sustained days of 30°C+, with heat stress affecting site workers, material curing, and project timelines.

What was once a "1-in-10-year event" has become disturbingly annual. Yet our legal mechanisms haven't caught up.

🏗️ NEC4’s “1-in-10” Weather Clause — Time for an Overhaul?

The NEC4 contract, widely used in the UK, includes provisions for compensation events if adverse weather surpasses a "1 in 10 year" statistical threshold. This clause hinges on historical weather norms—which are increasingly out of date in the face of climate change.

If we consistently hit that 1-in-10 threshold every other year (or even annually every summer), then we’re clearly operating in a new baseline. Persisting with outdated weather modelling in contracts puts both clients and contractors at risk—operationally, financially, and reputationally.

We must ask: Should NEC4 (and other forms) recalibrate how "exceptional" weather is defined—and more importantly, how its risks are shared?

🇦🇺 Lessons from Australia: Heat Is Safety First

Contrast this with Australia, where heat is no stranger. Enterprise Bargaining Agreements (EBAs), backed by Fair Work Commission rules, often stipulate that when temperatures exceed 35°C, outdoor work stops. No ambiguity. No prolonged negotiations. Just safety first.

These rules aren’t merely recommendations—they’re industrially enforced. Union protections ensure that productivity doesn’t come at the cost of health. It’s a hardline, but it provides certainty for all parties.

Why does this matter? Because clear rules protect not just workers, but project schedules too. There’s no second-guessing whether work should continue or whether claims for lost time are compensable—it’s built in.

🇬🇧 What Should the UK Do?

The UK doesn’t currently have equivalent automatic thresholds. While the Health and Safety Executive encourages sensible precautions, there's no regulatory floor for “too hot to work.”

That leaves a dangerous ambiguity.

Should this be addressed by statute, or at least through standardisation across JCT and NEC forms? I’d argue yes.

We need mechanisms that are:

• Data-informed: aligned with modern climatology, not past norms.
• Contractualised: written into forms that govern real work, not just policy memos.
• Worker-focused: prioritising wellbeing in a heating world.

🌍 Building Resilience in Contracts

Climate change isn’t a future event—it’s now. Whether we’re in Manchester or Melbourne, the same truth holds: extreme & 'exceptional' weather is no longer rare, and our contracts must stop treating it that way.

We need to move away from the idea of weather risk as an "unforeseen exception" and start designing legal frameworks that reflect the realities on site and be upfront about it. Why not be upfront about what days are expected to be lost to weather?

After all, change is upon us and our construction contracts need to adapt to a changing world.

What do you think? Have you had to manage projects during heatwaves this year? How do your contracts treat extreme weather? Let’s discuss 👇

#ConstructionLaw #NEC4 #Heatwave2025 #FairWork #ClimateRisk #Contracts #UKConstruction #Australia #WeatherResilience