Seasonal
Transitions

Why Seasons Matter for Skin

Your skin barrier operates in equilibrium with its environment. Temperature, relative humidity, UV index, wind, and indoor heating all directly affect transepidermal water loss, sebum production, and barrier lipid organisation. A routine optimised for cold, dry winter conditions will be too heavy, occlusive, and potentially problematic in hot, humid summer — and vice versa.

Winter: Fortify the Barrier

Cold temperatures constrict blood vessels → reduced sebum production. Low humidity → elevated TEWL. Indoor heating → additional moisture loss. Winter skin requires a barrier-first, occlusive-heavy approach.

Winter Adjustments

• Upgrade cleanser from gel to cream — reduces lipid stripping
• Add a hyaluronic acid serum before moisturiser to combat dehydration
• Switch to a richer ceramide moisturiser (cream vs gel format)
• Add a facial oil or petrolatum layer on top in the PM
• Reduce exfoliation frequency — barrier is already stressed
• Use a humidifier in sleeping environment (target 40–60% relative humidity)

Summer: Lighten and Defend

High heat → elevated sebum production. High humidity → skin may feel greasy with heavy moisturisers. High UV index → elevated photodamage risk. Summer skin requires lighter formulations and increased UV defence.

Summer Adjustments

• Switch to a gel or gel-cream moisturiser — lighter weight, still hydrating
• Elevate to SPF 50+ if not already — UV index is higher
• If prone to breakouts in summer: add BHA to routine or increase frequency
• Can reduce or eliminate heavy facial oils — replace with a lightweight squalane if needed
• Antioxidant serum (Vitamin C) becomes even more critical to counteract elevated UV-generated ROS
• Reapplication of SPF every 2 hours in direct sun

Transition Period Approach

What Changes	Winter → Spring	Summer → Autumn
Moisturiser	Gradually downgrade weight week by week	Gradually upgrade weight
Cleanser	Move from cream back to gel over 2 weeks	Move from gel toward cream cleanser
Exfoliation	Gradually increase frequency	Gradually reduce if skin is reactive
SPF	Maintain SPF 50 — UVA is year-round	Maintain SPF 50 — do not downgrade

For TEWL science that explains winter barrier breakdown, see TEWL. For sunscreen science, see Sun Filters.