Why it’s harder to wake up on dark winter mornings

In summer, the room is already bright when your alarm goes off. By December, it’s pitch black, the covers feel twice as heavy, and getting up feels like getting up in the middle of the night.

That last part is closer to the truth than it sounds. Your body clock takes its timing from light, and on a dark winter morning it gets very little of it before your alarm.

In short: dark mornings make waking harder mainly because your body clock runs later than your alarm, so you’re more likely to wake during your biological night, when grogginess is strongest. The fall time change briefly helps rather than hurts. What helps most is a consistent wake time, daylight early in the day, less bright light late at night, and possibly a sunrise-style light that brightens before your alarm.

When does daylight saving time end?

In most of the US and Canada, clocks fall back one hour on the first Sunday of November: November 1, 2026. In the UK and the EU, they go back on the last Sunday of October: October 25, 2026.

You gain an hour, and for a while mornings are lighter: with a 7 a.m. alarm, you wake after sunrise again for about two weeks in London and about a month in New York. Then sunrise keeps creeping later until around the turn of the year. In London, the latest sunrises come in late December and early January, at about 8 a.m. In New York, the latest sunrise of the year comes the day before the clocks fall back, at about 7:25 a.m., and sunrise is back after 7 a.m. by December.

To see how dark your own mornings get, our sunrise and first light calculator charts the year for your city.

Is the fall time change the hard one?

Usually not. Research on the twice-yearly time change finds the spring change is the disruptive one. In a study that tracked people’s sleep and activity around both transitions, their timing readily adjusted when the clocks fell back in the fall, but didn’t adjust when they sprang forward in spring, especially in people who are naturally late sleepers.¹ The American Academy of Sleep Medicine points to the spring change as the one with measurable health and safety risks, and calls for permanent standard time (winter time) because it fits human body clocks better.²

So the fall change itself isn’t really the problem. The problem is what follows: weeks of waking up before the sun.

Why are dark mornings harder?

Your body clock sets itself by light

Your circadian clock, the internal timer that decides when you feel sleepy and alert, is reset every day mainly by light. Morning light nudges it earlier; bright light late in the evening nudges it later.

Studies that sent people camping, with only natural light, show how much modern lighting changes this. After a week outdoors, people’s internal “biological night” started around sunset and ended just after sunrise, and their clocks ran earlier than at home with electric light.³ A follow-up study in winter found the same: away from electric light, sleep and the biological night started earlier. It also found that the biological night is longer in winter than in summer.⁴

At home in winter, we get the opposite combination: little daylight in the morning, and bright screens and lamps late into the evening. That pushes the body clock later, while the alarm stays put.

Waking in your biological night makes grogginess worse

This is where it connects to the groggy feeling after waking, known as sleep inertia. One of its biggest drivers is waking during your biological night: grogginess is most intense when your body clock still thinks it should be asleep.⁵ A later body clock plus an unchanged alarm means more mornings where your alarm lands in that window.

Sleep loss adds to it

Dark mornings often come with late nights. If your body clock runs later, you may fall asleep later but still get up at the same time, and short sleep makes sleep inertia stronger and longer.⁵

Do sunrise alarm clocks work?

Sunrise alarms, wake-up lights and smart bulbs set to brighten before your alarm all try the same thing: simulate dawn. Among the waking methods we’ve looked at, this has some of the better evidence, with a few important caveats.

• In a lab study, 16 people who found waking up difficult slept one night with an artificial dawn during the last 30 minutes of sleep and one without. After the dawn, they felt significantly less sleepy and more activated. There was no measurable difference in their performance on tests.⁶
• In a home study, people with difficulty waking used dawn-simulating alarm clocks for two weeks per condition. In both parts of the study, one testing set brightnesses of 50 and 250 lux and one letting people choose their own, the artificial dawn significantly reduced their complaints of sleep inertia. Interestingly, it didn’t shift their body clocks: the benefit seemed to come from the dawn signal itself.⁷
• In a small study of 8 people, a 30-minute simulated dawn improved ratings of sleep quality and alertness, and they were slightly faster on reaction-time and addition tasks after waking.⁸

The pattern: these studies are small, and the clearest effects are on how awake people feel, rather than on objective performance. But they consistently point the same way, and the light comes on before waking. Bright light switched on only at waking has looked much less helpful for grogginess in the studies that tested it.⁹ In other words, it’s the gradual dawn that seems to matter, not simply turning the big light on.

You don’t need an expensive lamp to try it. Many smart bulbs can be scheduled to brighten slowly over 20 to 30 minutes before your alarm.

Other things that help on dark mornings

Most of these are free.

• Keep your wake time steady, weekends included. Regular sleep and wake times are linked to better sleep and health, and a stable wake time keeps your body clock from drifting later.¹⁰ Sleeping in late on Saturday followed by a 6 a.m. Monday is a small jet lag every week. (If you’re a natural night owl, see How to wake up early when you’re a night owl.)
• Get daylight early. Daylight, even on an overcast winter day, is usually much brighter than indoor lighting. A walk, a commute on foot, or breakfast by a window in the first hour or two of the day all help anchor your clock.
• Dim the evenings. Bright light late in the evening pushes your clock later. Lower the lights in the last hour or two before bed, and keep screens dimmer.
• Get enough sleep. If winter mornings feel impossible, an earlier bedtime will likely do more than any wake-up trick.
• Make waking less abrupt. In the dark, a sudden beep is an especially rude start. A quiet, melodic sound that rises is gentler, and melodic sounds have been linked with less reported grogginess.¹¹ More in What makes a good alarm sound?

When it’s more than the dark

Most people find winter mornings harder; that’s normal. But if your mood drops noticeably every winter, or tiredness and low energy start to affect your daily life, it’s worth talking to a doctor rather than trying to fix it with an alarm clock.

How this shapes Jera

Jera can’t switch on your lights, so we won’t pretend it’s a sunrise lamp. If you have one, or a smart bulb, it pairs well with Jera: let the light rise, and let the sound rise with it.

What Jera does is make the sound side of waking gentle: it’s a gentle alarm clock for iPhone whose sound rises gradually to full volume at your alarm time. For dark months specifically, a Sunrise alarm can follow the actual sunrise where you are, recalculated every day, if your mornings are flexible enough to move with the seasons. If they aren’t, stick with a fixed time and keep it on weekends too.

Jera is designed to support a gentler wake-up. It isn’t a medical device, and if you regularly struggle to wake up or feel unrested, it’s worth talking to a doctor.

Frequently asked questions

Why is it harder to wake up in winter?

Your body clock is set by light. With little morning daylight and plenty of evening light, it tends to run later in winter, so your alarm is more likely to go off during your biological night, when grogginess is strongest.

Does the time change make waking up harder?

The fall change usually doesn’t: you gain an hour, and research suggests people adjust to it readily. The spring change is the harder one. In the fall, the bigger issue is the weeks of dark mornings that follow.

Do sunrise alarm clocks really work?

Small studies suggest that light gradually brightening in the last 30 minutes before waking helps people feel less sleepy and more alert after waking. Effects on objective performance are less consistent. Light that only comes on at waking seems to help less.

What’s the best way to wake up when it’s dark?

Keep the same wake time every day, get daylight soon after waking, dim the lights in the evening, get enough sleep, and use a gentle, rising alarm. A light that brightens before your alarm may help too.

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