When the Light Changes: How Longer Days Can Affect Sleep, Mood & Regulation

As February fades and March approaches, many families begin to notice it — the sun lingering a little longer in the evening, brighter mornings, and children who seem to have just a bit more energy.

Seasonal light changes may feel subtle to adults, but for many autistic children, shifts in daylight can meaningfully impact sleep, mood, attention, and overall regulation.

With Daylight Saving Time arriving on March 8th and spring around the corner, it’s helpful to understand how light interacts with the nervous system — and what families can gently adjust during this transition.

Why Light Matters So Much to Sleep, Mood & Regulation

Light is one of the strongest regulators of our circadian rhythm — the internal clock that tells our body when to feel alert and when to feel sleepy.

For children with autism, circadian rhythms can sometimes be more sensitive or less predictable. Even small shifts in:

• Morning brightness

• Evening sunset timing

• Screen exposure after dark

can influence:

• Sleep onset (trouble falling asleep)

• Early waking

• Afternoon irritability

• Increased sensory sensitivity

• Bursts of hyperactivity or “zoomies”

When bedtime suddenly feels “too bright,” the brain may not release melatonin as easily, which can lead to later bedtimes and more fragmented sleep.

What You Might Notice at Home

During this time of year, caregivers often report:

• Bedtime resistance increasing

• Children seeming “wired” at night

• Earlier morning wake-ups

• More impulsivity after school

• Emotional dysregulation that feels sudden

It’s important to remember: this isn’t misbehavior.It’s often biology.

When sleep shifts even slightly, regulation follows.

Gentle Ways to Support the Transition

Rather than overhauling routines, small environmental adjustments can make a meaningful difference.

Strengthen Morning Light

Expose children to natural light early in the day:

• Open curtains right away

• Eat breakfast near a window

• Step outside briefly before school

Morning light helps anchor the body clock.

Dim the Evenings Earlier

As sunset moves later:

• Lower indoor lighting after dinner

• Use warmer light bulbs if possible

• Reduce bright overhead lighting

Think “calm cave” energy as bedtime approaches.

Encourage Outdoor Movement Before Dinner

Spring energy is real. Outdoor movement:

• Regulates the nervous system

• Supports sleep pressure

• Reduces evening restlessness

Heavy work activities (pushing, pulling, climbing) can be especially grounding.

Protect the Wind-Down Window

Screens and bright devices close to bedtime can delay melatonin release. If possible:

• Lower screen brightness

• Shift to quieter, lower-light activities in the final hour

• Keep the bedroom environment cool and dark

A Note for Caregivers

Seasonal transitions can feel layered. While children may have more physical energy, parents are often still carrying winter fatigue.

If bedtime stretches longer or evenings feel harder for a few weeks, you are not doing anything wrong.

The nervous system is simply adjusting.

Give yourself permission to:

• Lower expectations temporarily

• Focus on sleep protection

• Let small wins count

Ten extra minutes outside in the afternoon can sometimes do more than an hour of troubleshooting at night.

For Referral Partners

Late winter and early spring often bring:

• Mild sleep regression

• Increased impulsivity

• Heightened sensory seeking

• Emotional variability

When behavioral changes appear this time of year, it may be helpful to ask about recent sleep shifts or changes in light exposure. Supporting circadian regulation can sometimes ease symptoms without additional intervention.

Collaborative awareness during seasonal transitions can help families feel supported — rather than overwhelmed.

As the days grow longer, we have an opportunity to work with these changes instead of against them. With small environmental adjustments and gentle observation, many families find that regulation steadies again as the body adapts.

At Georgia Autism Center, we’re here to help families navigate every season — including the brightening ones.