Why Does Rainy Weather Affect Your Mood? - The Psychology of Grey Days

by Suzie Booth, Psychotherapist (MSc. MBACP accred).

Grey skies. Endless drizzle. That strange feeling of heaviness that seems to creep in without a clear reason, other than the weather.

Many people notice that during periods of consistent rainy weather, their mood shifts. They feel more tired, less motivated, more irritable, or just… flat.

This isn’t imagined. Weather genuinely can influence how we feel, both psychologically and physiologically...

1. Light Levels & The Brain

One of the biggest mood-shifting factors isn’t actually the rain itself, it’s the lack of sunlight.

Natural daylight plays a key role in regulating:

• Serotonin (linked to mood stability and wellbeing)

• Melatonin (linked to sleep and energy)

• Circadian rhythms (your internal body clock)

When light levels drop:

• Serotonin production can decrease → mood dips

• Melatonin regulation shifts → you feel sleepier/sluggish

• Your body clock can feel slightly “out of sync”

This is why prolonged grey weather can leave you feeling more fatigued or low, even if nothing else in your life has changed.

2. Rain & Behavioural Changes

Rain doesn’t just change the sky, it changes how we live.

Consistent rainy weather often means:

• Less time outdoors

• Reduced physical activity

• Fewer spontaneous social interactions

• More time inside

All of which subtly impact mood.

Movement, daylight exposure, and social connection are powerful regulators of emotional wellbeing. When these decrease, mood often follows.

It’s not weakness. It’s human biology interacting with environment.

3. The Psychological Weight of Grey

Weather also carries emotional symbolism.

Bright, sunny days often feel energising, expansive, hopeful.

Grey, rainy days can feel:

• Heavy

• Confining

• Muted

• Slower

For many people, the external environment mirrors internal experience.

If the world looks dull and subdued, our internal landscape can start to feel similar. Our nervous system is constantly responding to cues from our surroundings.

4. Loss of Micro-Pleasures

Something we rarely acknowledge:

Rain disrupts small, everyday sources of joy.

Walks feel less appealing. Outdoor plans get cancelled. Children’s energy builds indoors. Simple routines become harder.

These tiny losses accumulate.

Mood is not shaped solely by big life events. It is heavily influenced by daily micro-experiences; light, movement, novelty, pleasure, ease.

Rain quietly erodes many of these.

5. Why Some People Feel It More Than Others

Not everyone reacts to rainy weather in the same way.

Sensitivity can be influenced by:

• Baseline mental health

• Stress levels

• Lifestyle (outdoor vs indoor routines)

• Personality & nervous system differences

• Seasonal patterns

For someone already feeling depleted, grey weather can amplify that sense of heaviness.

For someone well-rested and regulated, it may barely register.

A Final Thought

If you’ve felt more tired, irritable, or flat during long stretches of rain, you are not 'being dramatic.'

Your brain and body are responding to real environmental changes.

Sometimes mood shifts are not psychological mysteries.

Sometimes… it’s just February in the UK.

And your nervous system doing exactly what nervous systems do.