What tog if the bedroom drops overnight UK?

Why do brand tog charts miss an overnight drop?

A hang-tag has one column: room °C → tog + clothing. It does not have a 10pm / 5am split. UK housing does. A terrace with night-setback heating, a room over an unheated hall, or a solid-wall bedroom can read 19°C at bedtime (NHS 2.5 tog band) and 14°C before dawn (below the Lullaby Trust 16–20°C sleep-space).

If you dress for the bedtime number only, the 5am number is the one the chest will meet. If you dress for a guessed 14°C all evening, you start the night in a room the NHS still calls a 2.5 tog room. The missing how-to is measure the drop, then pick clothing or tog for the coldest cot-height reading you actually see, without putting a blanket on the bag.

What does Lullaby Trust say about heating all night?

On the room-temperature page they answer the winter bill question directly: it is rarely necessary to keep the heating on all night, and adding an extra layer will usually help if you cannot hold 16–20°C. Which? repeats the NHS line that all-night heating is rarely necessary, and aims for 16–20°C regardless of the outdoor forecast.

If you still choose to leave heating on, Lullaby Trust says set it low, and no higher than 20°C. That is a cap, not a prescription to keep the boiler on. Which? also says a portable heater can warm the room to 16–20°C before bedtime, then should be switched off and taken out of the room — not left running beside the cot.

This page does not tell you to keep heating on. The official alternative to a 5am drop is clothing or a higher tog, plus a thermometer, not a MayTally thermostat setting.

How do I measure the drop at cot height?

Guessing from how the landing feels at 10pm is how 19°C/14°C nights get treated as a single 18°C chart row.

1. 1
   Put the thermometer where the baby sleeps Cot height, not the radiator shelf and not the hallway. Lullaby Trust: it is hard to guess, so use a room thermometer in the rooms used for sleep.
2. 2
   Write down bedtime and before-dawn readings for a few nights Same clock time each night if you can. One mild night is not a climate. You are looking for a repeatable drop, not a one-off open window.
3. 3
   Map both numbers to the NHS list 16–20°C → 2.5 tog. 20–24°C → 1.0 tog. 24–27°C → 0.5 tog. A bedtime 19°C and a dawn 17°C are still one official band. A bedtime 19°C and a dawn 14°C have left it.
4. 4
   Decide clothing or tog against the coldest repeatable reading Lullaby Trust: if the room is colder than 16–20°C, add a clothing layer or choose a higher tog. Do not add a blanket on the bag. Recheck the chest or neck during the first nights you change the setup.

Do I change tog or add a clothing layer?

Lullaby Trust names both. NHS does not publish a 14°C bag. Which? winter examples fill that shop-chart gap — treat them as Which?, not as an extra NHS band.

What should I avoid when the room feels cold at 5am?

• A blanket, quilt or folded sheet on the sleeping bag. Lullaby Trust and Which? both close that workaround. NHS: no other bedding with a bag.
• A hat in the cot. Lullaby Trust: heads lose heat; covering them indoors can mean the baby gets too hot.
• Hot water bottles, wheat bags, electric blankets. Which? / RoSPA: burn and overheating risk for infants.
• The cot pushed against the radiator to "make up" the drop. Lullaby Trust: keep the sleep-space away from heat sources.
• Two sleeping bags stacked. Lullaby Trust: trapped air between bags is not a tidy tog sum.
• A 2am tog change as the default. If the drop is real and repeatable, set clothing or tog at bedtime for the dawn reading you logged — then check the chest, rather than re-dressing a sleeping baby every night.

In shortLog cot-height bedtime and before-dawn temperatures for a few nights. Lullaby Trust: heating all night is rarely needed; add clothing or a higher tog if the room sits below 16–20°C — not a blanket on the bag. Brand charts that assume a flat 19°C miss the UK terrace drop.