Laying tarmac is a job best done in the right weather. While tarmac is a tough, reliable surface, it’s highly sensitive during installation — and getting the timing wrong can result in cracks, poor bonding, or a shorter lifespan. So when shouldn't you lay tarmac? And when is the best time to do it?

Let’s break it down.

Why Weather Matters When Laying Tarmac

Tarmac (or asphalt) needs to be laid hot and compacted quickly before it cools. This means temperature, humidity, and ground conditions all affect how well the surface sets. If it cools too fast, or is disturbed by rain, the result is often a compromised finish.

When Not to Lay Tarmac

❄️ In Cold Weather (Below 12°C)

When the temperature drops below around 12°C, tarmac begins to cool too quickly. This prevents proper bonding and compaction — leading to weak spots or cracks.

It’s even worse if the ground itself is cold or frozen, as the layers underneath won’t settle properly either.

Bottom line: Avoid laying tarmac during late autumn, winter, or early spring unless conditions are mild and dry.

🌧 During Wet or Rainy Conditions

Rain and tarmac don’t mix. If it starts raining while the surface is being laid or compacted, moisture can get trapped — weakening the structure and leaving visible blemishes or pothole-prone spots.

Contractors will often postpone a job if there’s even a moderate chance of rainfall during installation.

🥶 In Frosty or Icy Conditions

Frost is a double threat: it affects both the tarmac and the ground underneath. Even if the surface appears dry, residual moisture can expand during freezing conditions and disrupt the curing process.

So, When Is the Best Time to Lay Tarmac?

The best conditions are:

• Dry
• Mild (between 12°C and 25°C)
• Stable weather forecast for 24–48 hours

This usually means late spring to early autumn in the UK, typically between April and October, depending on location.

Warm temperatures give you more working time before the tarmac cools, and dry conditions ensure a smooth, even finish without water damage.

Can You Lay Tarmac Outside These Conditions?

Yes, but with caution.

Professional contractors may use accelerators, heated tools, or rapid-set materials in cooler conditions. In warmer months, they may work early in the day to avoid surface softening or overheating.

The key is planning: the right preparation, materials, and timing can make or break the result.

Final Thoughts

Tarmac is one of the most cost-effective and durable surfaces out there — but only when laid correctly. Avoid laying it in cold, wet, or frosty conditions, and aim for dry, mild weather whenever possible.

If you're unsure, it’s always best to speak to a local specialist who can advise based on forecast and ground conditions.