Why You Stay Up Later When the Clocks Go Forward

You stay up later after daylight saving because the light does, not because you need less sleep. An extra hour of evening sun delays the body's melatonin rise, so the signal to wind down arrives late while the alarm stays exactly where it was. The gap is roughly an hour, and it compounds across the week.

In short

• New Zealand's clocks go forward at 2am on Sunday 27 September 2026, jumping straight to 3am, which makes that night one hour shorter.
• Evening light suppresses melatonin and blunts the usual evening fall in core body temperature, and that fall is the physiological signal that lets sleep begin.
• Researchers at Utrecht University named bedtime procrastination in 2014, defining it as going to bed later than you intended when nothing external is stopping you. It tracked with self-regulation rather than with how tired people were.
• Massey University's Sleep/Wake Research Centre reports that nearly a quarter of New Zealanders sleep less than seven hours a night on days they work or study.
• Sleep starts when heat leaves the body through the hands, feet and face, so a warm bedroom and a heat-holding pillowcase both work against you.
• A wind-down that begins before you feel tired beats willpower at 11pm, because by then the decision has already been made for you.

Why does daylight saving make it harder to get to sleep?

Daylight saving makes sleep harder because it moves the clock without moving the body. Your circadian timing runs on light, chiefly the light your eyes take in during the last few hours before bed, and on the last Sunday of September that light suddenly stretches an hour deeper into the evening. The clock says half past nine. Your retinas say late afternoon.

What follows is predictable. Melatonin, which normally begins rising a couple of hours before sleep, is pushed back by the extra light. Core body temperature, which has to fall for sleep to begin, holds high a little longer. Meanwhile Monday morning arrives at the same moment it always did. Nothing has changed except the number on the phone, and yet the whole household is a beat behind.

It is worth saying plainly that this is a small effect, not an illness. Most people resettle within a week. But it lands on top of something else, and that combination is what makes late September in Auckland feel harder than it should.

What is bedtime procrastination?

Bedtime procrastination is going to bed later than you meant to when nothing is actually preventing you from going. The phrase came out of Utrecht University, where Floor Kroese and colleagues introduced it in Frontiers in Psychology in 2014 after surveying a community sample of 177 adults. Their finding was the interesting part. People who put off bedtime were not busier or more disturbed than anyone else. They scored lower on self-regulation, the same capacity that governs every other intention we form in the morning and abandon by evening.

Anyone who has ever sat on the end of the bed at 11.40pm, phone in hand, fully aware of what tomorrow looks like, recognises this. It is not insomnia. It is the opposite of insomnia. You are not lying awake wanting sleep. You are awake, choosing not to go, and the choosing feels oddly like a small act of ownership at the end of a day that belonged to other people.

The internet has since renamed it revenge bedtime procrastination, which overstates the revenge and understates the procrastination. The original framing is more useful. If the problem is self-regulation rather than desire, then the fix is structural. You change the conditions, not the resolve.

Why does the last hour of the evening decide the night?

The last hour of the evening decides the night because sleep onset is a heat problem before it is anything else. To fall asleep, your core temperature has to drop, and the way a body sheds heat is through the hands, the feet and the face, where the blood vessels sit close to the surface. Sleep researchers measure this as the distal-proximal gradient, the difference between how warm your extremities are and how warm your trunk is, and it has turned out to predict how quickly someone falls asleep better than core temperature itself does.

That is why a hot bath forty minutes before bed works, counter-intuitive as it sounds. You warm the surface, the vessels open, and then heat pours off you afterwards. It is also why a stuffy bedroom in a New Zealand spring, when nobody has quite worked out whether to open the window yet, makes the first twenty minutes under the duvet so restless.

Evening light interferes with both halves of this. It suppresses melatonin, and it blunts the temperature decline that melatonin normally accompanies. Daylight saving hands you an extra hour of exactly that, every night, for six months.

How long does it take to adjust to the clock change?

Most people adjust to the spring clock change within about a week, shifting roughly ten to fifteen minutes a night until the body catches up with the clock. Morning light does most of the work. Getting outside within an hour of waking on the Sunday and Monday after the change pulls your timing forward faster than anything you do at night.

The people who take longer are usually the ones already running a sleep debt. The Sleep/Wake Research Centre at Massey University has found that nearly a quarter of New Zealanders sleep under seven hours on working days, and that around a third of those short sleepers shift their sleep substantially at weekends, a pattern the researchers call social jetlag. If that is already your week, daylight saving is not a one-off hour. It is another hour on an existing tab.

What actually helps in the week after the clocks change?

What helps is starting the wind-down earlier than feels necessary and making the bedroom dark and cool enough that your body is not fighting the room. Five things, in rough order of how much difference they make:

1. Get morning light early. Ten minutes outside before 9am on the Sunday and Monday shifts your clock forward more reliably than any evening intervention.
2. Pick a wind-down time, not a bedtime. Set an alarm for forty minutes before you want to be asleep. The alarm is for putting things down, not for getting into bed.
3. Make the last hour dimmer, not darker. Lamps rather than overheads. You do not need to sit in the dark. You need to stop telling your retinas it is still afternoon.
4. Cool the room before you cool yourself. Open the window at eight, not at eleven. A bedroom around eighteen degrees gives your body somewhere to send its heat.
5. Block what you cannot control. Spring evenings in Auckland stay light past eight, and by December it is light until nine. If your curtains were chosen for winter, they are now the weak point in the room.

Where does silk fit into any of this?

Silk fits in two modest places, and it is worth being honest about how modest they are. No fabric will fix a bedtime you keep pushing back. What a fabric can do is stop adding friction to the part of the night you have already got right.

The first is light. If the reason you are awake at ten past ten is that the room still reads as evening, an eye mask removes that argument entirely, and a soft one is more likely to stay on your face than a stiff one. We have written at more length about whether silk eye masks really help you sleep, and about the case for genuine darkness if light sensitivity is part of your picture.

The second is heat, and this is where silk earns its place rather than being decorative. Your face is one of the three surfaces your body uses to shed heat at sleep onset. Mulberry silk is a protein fibre, close in composition to the keratin in your own skin and hair, and it holds moisture without holding warmth against you the way a brushed or synthetic surface does. It is the reason a silk pillowcase feels cool for the first few seconds and then simply feels like nothing, which is what you want from something your cheek rests on for seven hours. The same property works in reverse in July, which we cover in why silk suits hot sleepers.

If you want the fuller account of what a pillowcase does and does not do overnight, our guide to what actually happens to your skin while you sleep is the place to start.

Common questions about daylight saving and sleep

When exactly does daylight saving start in New Zealand in 2026?

Daylight saving starts at 2am on Sunday 27 September 2026, when clocks jump forward to 3am and New Zealand moves from NZST to NZDT. That Sunday is 23 hours long. Daylight saving then runs until the first Sunday in April, when the clocks go back again.

Should I go to bed earlier the night before the clocks change?

Going to bed fifteen to twenty minutes earlier on the Friday and Saturday before the change softens the landing more than one large early night does. A single early bedtime usually just means lying awake, because your body is not ready for sleep at a time it has no reason to expect.

Is bedtime procrastination the same as insomnia?

Bedtime procrastination is not insomnia. Insomnia is wanting to sleep and being unable to. Bedtime procrastination is being able to sleep and choosing not to go yet. The two can overlap, but the remedies differ, and persistent insomnia is worth raising with your GP rather than solving with a better evening routine.

Does an eye mask help if my curtains already block most light?

An eye mask helps most when light is reaching you at the edges, which is common with curtains fitted to the window rather than the wall. If your room is genuinely dark at 9pm in December, a mask adds little. If you can read your phone screen reflected in the wardrobe door, it adds a lot.

What room temperature is best for falling asleep?

Most sleep research points to a bedroom between about sixteen and nineteen degrees for falling asleep comfortably. The exact number matters less than the direction. A room that is cooler than your body gives your hands, feet and face somewhere to send heat, which is what starts the process.

If your curtains are about to be outvoted by six months of long evenings, a silk sleep mask is the smallest useful thing you can change this week.

The hour goes forward on Sunday whether or not any of us are ready for it. What we get in return is light at the end of the day, the smell of cut grass at seven in the evening, dinner outside for the first time since March. The trade is a good one. It only asks that you decide, in advance and while you still have the wit to mean it, what time the evening ends.