Sarah Clarity Studios

Sunrises and Sunsets

Created by Sarah Choi (prompt writer using ChatGPT)

Sunrises and Sunsets — An In‑Depth Guide

Sunrise and sunset are daily stage changes—our turning Earth sweeping the Sun into and out of view while the atmosphere paints light across the sky. The show is universal, yet no two performances are alike. Local air, temperature, moisture, dust, clouds, and terrain remix the same physics into different colors and rhythms around the world. This article explains how sunrises and sunsets happen, why their colors vary, and how geography and climate—from equatorial coasts to polar deserts—shape what we see.

How Sunrise and Sunset Happen

Sunrise and sunset are not the Sun moving, but Earth rotating. As your location spins toward daylight (sunrise) or away from it (sunset), sunlight meets the atmosphere at a very shallow angle and must traverse a long, slant path through air. Along this path, molecules and particles scatter and absorb light.

Two physical effects dominate:

Rayleigh scattering. Air molecules are much smaller than visible wavelengths. They scatter short wavelengths (violet/blue) much more strongly than long wavelengths (red/orange). When the Sun is high, scattered blue light fills the sky. Near the horizon, the extra air path removes most blues along the direct line of sight, so the transmitted sunlight is reddened.

Mie scattering and absorption. Larger particles—dust, smoke, salt spray, water droplets—scatter all wavelengths more evenly (whitening) and can absorb light, muting or deepening colors depending on composition. Thin haze can make sunsets pastel; volcanic aerosols or wildfire smoke can produce saturated reds and purples.

Refraction. The atmosphere bends (refracts) light, lifting the apparent Sun by roughly half a degree near the horizon. Official sunrise/sunset times are defined when the Sun’s upper limb just touches the horizon, already accounting for standard refraction and the Sun’s apparent radius. Temperature gradients and inversions can change refraction slightly, shifting times by minutes and warping the Sun’s shape into ovals or mirage‑like stacks.

Twilight bands. After sunset (or before sunrise), the Sun continues to illuminate the upper atmosphere. We divide twilight by the Sun’s depression angle below the horizon: civil (0–6°), nautical (6–12°), and astronomical (12–18°). Civil twilight is the “golden hour” for warm light; nautical twilight brings the Belt of Venus—a pink anti‑sunset arch above a bluish Earth’s‑shadow band; astronomical twilight ends when a truly dark sky returns.

The Color Story

A classic sunset often unfolds in acts. With the Sun low but still above the horizon, warm direct light bathes the ground while the sky overhead remains blue. As the Sun touches the horizon, its disk yellows and oranges. Immediately after it sets, high clouds—especially cirrus and altocumulus—can blaze pink to crimson as they catch sunlight from below while lower clouds fall into shadow. The final act features deep purples as the remaining red light mixes with blue scattered from higher, still‑lit air. If conditions align, a fleeting green flash may sparkle at the last instant: atmospheric dispersion and temperature layering let a thin, green upper edge of the Sun linger a heartbeat longer than red and orange.

Cloud type sets the canvas. Low, thick stratus often dulls colors; broken cumulus can produce dramatic shafts of light and shadow (crepuscular rays); high, wispy cirrus deliver fiery afterglows. In winter, flat snowfields reflect and amplify color; over water, ripples mirror the sky’s gradient.

Around the World: Geography’s Signature

Equatorial regions. Near the equator the Sun’s path is steep; day transitions are quick. Civil twilight can last only 20–25 minutes. Maritime humidity and tropical convection favor towering cumulus and late‑day thunderstorms; sunsets can be vivid beneath anvils, with dramatic rays fanning across humid haze. Islands ringed by salt spray often show bright orange disks and broad, white crepuscular rays.

Midlatitudes. In temperate zones, twilight length varies by season—shorter near the equinoxes, longer toward solstices. Autumn often brings striking clarity after cold fronts sweep out haze. Spring dust or pollen can warm tones. Coastal west‑coast locations (e.g., under onshore flow) see sunsets filtered through marine layers that turn pastel.

Polar regions. Above the Arctic/Antarctic Circles, the Sun can graze the horizon for hours. In late spring and late summer, “golden hour” stretches into a golden day, with the Sun circling obliquely—a continuous, low‑angle illumination prized by photographers. In winter, polar night brings blue and purple twilights at midday. Ice crystals in frigid air create sun pillars, parhelia (sun dogs), and 22‑degree halos, especially at sunrise and sunset when light crosses long slant paths through crystal‑laden layers.

High mountains and plateaus. Elevation shortens the atmospheric path, sharpening distant visibility and intensifying contrast. Temperature inversions in valleys trap haze below, so observers above a cloud or smog deck witness glowing “seas of cloud” (stratus) with peaks lit rosy by alpenglow—reddish illumination on mountains opposite the Sun caused by forward‑scattered red light and the pink anti‑twilight arch.

Deserts. Dry air and dust produce bold, clean horizons and saturated oranges. Dust storms (haboobs) can mute midday light yet yield coppery sunsets. Night‑to‑day temperature swings foster inversions that accentuate refraction, flattening the solar disk.

Coasts and oceans. Marine aerosols and uniform horizons showcase textbook green flashes and mirror‑perfect reflections. Sea fog can make the Sun a pale peach coin. Trade‑wind cumulus fields produce repeating bars of light and shadow at sunset as cloud streets line up with the wind.

Cities. Urban aerosols and pollution increase Mie scattering. Colors skew from orange to brownish if soot and nitrogen compounds absorb blue light, but after cold fronts scrub the air, city sunsets can be spectacular, with skyscrapers catching layered hues.

Climate, Weather, and Temperature: Why Conditions Matter

Humidity and temperature. Warm, humid air is rich in aerosols and water droplets that broaden scattering, softening contrast and shifting palettes toward pastels. Cold, dry air reduces haze and deepens sky blues, making the red/blue separation cleaner and the Belt of Venus more distinct. Sharp temperature inversions near the surface can create superior mirages—stacked, shimmering images—that stretch and split the solar rim at the horizon.

Cloud microphysics. Ice‑crystal optics emerge in subfreezing air: hexagonal plates and columns reflect and refract low Sun rays into pillars and sun dogs. In warmer storms, anvils of ice above thunderheads catch post‑sunset light; mammatus pockets glow peach and magenta beneath.

Aerosols: dust, smoke, and volcanoes. Fine smoke from wildfires reddens the Sun and Moon, often producing eerie orange daylight and crimson sunsets; larger ash can gray them out. Volcanic eruptions that loft sulfur dioxide into the stratosphere form sulfate aerosols that persist for months to years, yielding globally enhanced twilight purples and long‑lasting afterglows as high layers remain sunlit well after local sunset.

Seasons and monsoons. In monsoon climates, pre‑monsoon dust brings warm tones; during the wet season, towering convective clouds frame dramatic, rapidly changing color. In winter midlatitudes, frequent frontal passages alternate crystal‑clear evenings (post‑frontal) with muted, milky sunsets (pre‑frontal cirrostratus).

The Moving Stage: Where and When to Look

Azimuth drift through the year. Sunset and sunrise do not always occur due west and due east. They slide north and south along the horizon between solstices, reaching their widest extremes near June and December and crossing due east/west at the equinoxes. Local topography—mountains, buildings, treelines—shifts the apparent position and timing, delaying sunrise or hastening sunset as the Sun dips behind foreground relief.

Duration and rhythm. At the equator, the Sun drops fast; at high latitudes, it lingers. Over water, the final moments can be sudden; over broken terrain, the Sun may set twice as it slips behind successive ridges, each edge spawning a new burst of color as the direct beam is briefly interrupted and then resumed.

Twilight layering. After the disk disappears, stay a while. The brightest color often peaks 5–20 minutes later when high clouds catch light from below. The anti‑solar sky can be as beautiful as the sunset itself: look for the pink Belt of Venus arching over the rising slate‑blue Earth’s shadow.

Common Optical Companions

Crepuscular and anticrepuscular rays. Sunbeams and shadows cast by clouds appear to radiate from the Sun (crepuscular) or converge opposite the Sun (anticrepuscular). They are nearly parallel but seem to fan out by perspective.

Sun pillars. A vertical shaft of light over the rising or setting Sun, caused by reflection from flat, gently tumbling ice crystals.

Halos and sun dogs. Rings and bright parhelia 22° to either side of the Sun form when light refracts through hexagonal crystals; best seen in cold, crystal‑rich air.

Green flash. A seconds‑long emerald rim at the upper edge of the Sun as it sets or rises, favored by clear, distant horizons (ocean, high deserts) and stable temperature layering.

Bringing It Together

The physics of sunrise and sunset is universal—Earth turns, light scatters and refracts—but the atmosphere is a living filter. Climate and temperature set particle loads and crystal types; winds and seasons choreograph clouds; mountains and oceans edit the horizon. That is why the same Sun, seen from two places on the same evening, can tell different stories. To learn those stories, linger through the entire transition, turn around to watch the opposite sky, and pay attention to the air you are breathing—its moisture, its chill, its dust. You will begin to read the sky not just as color, but as the daily handwriting of your local climate on the canvas of light.