How Weather Affects Sunrise and Sunset Colours

Why Sunrises and Sunsets Have Colour

At sunrise and sunset, sunlight travels through more atmosphere than at midday. Short blue wavelengths scatter away, leaving longer red, orange, and pink wavelengths to dominate the sky.

Conditions for the Best Colours

High, Thin Clouds

Mid-to-high clouds (altocumulus, cirrus) act as a canvas, reflecting and scattering the warm light. Low, thick clouds block the light entirely.

Clean Air After Rain

Rain washes particles from the atmosphere. The cleaner air that follows produces purer, more vivid colours. Some of the best sunsets happen the evening after a storm passes.

Moderate Humidity

Some moisture in the atmosphere enhances scattering and colour. Bone-dry air produces pale sunsets. Moderate humidity adds depth and variety.

Volcanic Aerosols

Major eruptions inject sulphur particles into the stratosphere, producing exceptionally vivid sunsets worldwide for months. After Krakatoa (1883), sunsets were so red that fire brigades were called out.

Sunrise vs Sunset

Sunrises often produce cleaner, subtler colours because the atmosphere is calmer and contains fewer particles in the morning. Sunsets tend to be more dramatic because daytime heating stirs up dust and moisture.

Photographer's Rule of Thumb

• Clear west + clouds overhead at sunset = vivid colour
• Rain clearing from the west at sunset = spectacular potential
• Thick overcast everywhere = grey and dull
• Completely clear sky = colour at the horizon only, no cloud canvas

Predicting Great Sunsets

Check the forecast for:

1. Mid-level cloud cover (30-70% is ideal)
2. Clear skies toward the western horizon
3. Recent rain or storm passage
4. Moderate humidity

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Check sunset conditions on Weather Tomorrow.