Is Merino Wool Too Hot for Summer Workouts?

Wool has a reputation for being warm, which makes a lot of people assume merino isn’t suitable for summer or sweaty workouts. If you train in warm weather, this concern is completely reasonable.

The answer depends less on the word “wool” — and more on how merino actually manages heat and moisture.

The short answer

No — merino wool is not too hot for summer workouts. In many warm or humid conditions, merino can actually feel cooler and more comfortable than synthetic activewear, because it manages moisture differently and helps regulate skin temperature.

Why heat buildup happens during workouts

Feeling “too hot” during exercise is usually caused by trapped moisture, not insulation. When sweat sits on the skin or inside fabric, it prevents heat from dissipating efficiently.

This is why some lightweight, fast-drying fabrics still feel clammy or stifling in warm conditions.

How merino behaves in heat and humidity

Merino wool manages moisture at the fibre level rather than just on the surface. This changes how heat feels during movement:

Moisture vapour is absorbed into the fibre instead of pooling on the skin
Evaporation happens more gradually, reducing that sticky, overheated feeling
Skin temperature stays more stable during prolonged movement

This is why many people find merino more comfortable in heat and humidity than expected.

Why “quick-dry” fabrics can still feel hotter

Synthetic activewear is often designed to dry quickly on the surface. While that sounds ideal, it can leave sweat sitting between the fabric and your skin.

In warm conditions, that trapped moisture can actually make you feel hotter. For a deeper explanation, see why fast-drying activewear still smells — and feels worse in heat .

When merino might feel warm

Merino isn’t immune to physics. It can feel warm if:

The garment is unusually thick or layered
Airflow is very limited
The fabric stays damp for long periods

In normal summer training conditions, properly designed merino activewear is unlikely to feel “too hot”.

Related guides

If you’ve avoided merino because you assumed it would be too warm, summer workouts are often where its moisture-management benefits become most noticeable.