Summer nights in the UK aren't always warm, but when they are, sleep can become genuinely difficult. Stuffy bedrooms, warm bedding and the wrong sleepwear combine to create an uncomfortable night. The good news is that what you wear to bed has a measurable effect on how well you sleep in the heat.
How body temperature affects sleep
Your core body temperature naturally drops slightly as you fall asleep. This drop is actually part of the signal to your brain that it's time to rest. When the environment is too warm, your body struggles to make that temperature drop efficiently, which delays sleep onset and causes more waking during the night.
The goal of warm-weather sleepwear is to help — not hinder — that natural cooling process.
What to wear
Lightweight, breathable fabrics
The single most important factor is fabric weight and breathability. You want something that:
- Lets heat escape from your body rather than trapping it
- Moves air between the fabric and your skin
- Doesn't cling when you perspire
Viscose is an excellent warm-weather option. It's lightweight, smooth and allows air to flow through it. It doesn't retain heat the way cotton flannel or polyester does, and it stays feeling dry against the skin rather than becoming damp and uncomfortable.
Lightweight cotton voile or lawn (a very fine weave) is another option if you prefer natural fibres, though it tends to be less widely available in sleepwear styles.
Loose silhouettes
Fitted sleepwear restricts airflow. On a warm night, a relaxed wide-leg trouser and a loose top or a flowing nightdress will feel significantly cooler than fitted shorts and a body-skimming vest. The space between fabric and skin allows a thin layer of air to circulate, which helps with cooling.
Shorter lengths
Full-length pyjama sets are practical in autumn and winter, but in summer, shorter styles — above-the-knee nightdresses, or cropped wide-leg trousers — allow more heat to escape from the legs and feet.
Minimal fastenings
Buttons, elasticated cuffs and tight waistbands trap heat around specific points of the body. Look for wide elasticated waistbands with good stretch, and open or loose-fitting tops.
What to avoid
Polyester is the main fabric to avoid. It has poor breathability, traps heat and can feel clammy. Many cheaper pyjamas contain polyester or polyester blends — always check the fabric composition before buying.
Tight, body-hugging cuts restrict the movement of air around your body. Even in a light fabric, a fitted style will feel warmer than a loose one.
Dark colours absorb more radiant heat. On very warm nights, lighter colours — whites, creams, soft pastels — are marginally cooler than navy, black or deep tones.
Heavy elastication at wrists and ankles — cuffed styles designed to stay neat can trap heat at the extremities. Loose, open hems allow heat to escape.
Other tips for hot nights
- Cool a hot water bottle in the freezer — a frozen hot water bottle wrapped in a thin cloth placed at the foot of the bed can help cool you down quickly
- Sleep with socks off — the soles of your feet are key heat-dissipation points; keeping them uncovered helps your body regulate temperature
- Lightweight single duvet — a 4.5 tog or 7.5 tog duvet is better than heavy winter bedding in summer; many people also find a single sheet enough on very warm nights
- Pre-cool the room — keep curtains or blinds closed during the day to block heat from sunlight; open windows at night when the outside temperature drops
- Take a warm (not cold) shower before bed — counterintuitively, a warm shower helps the body's cooling mechanism trigger more efficiently than a cold one
The right balance
You don't have to sacrifice style for comfort in summer. A well-chosen lightweight nightdress in a relaxed cut, or a viscose pyjama set in a straight-leg style, can feel both elegant and genuinely cool on a warm night.
The key is choosing a fabric that actively helps your body regulate temperature rather than working against it.