Plural of “sky”

The plural of sky is skies.

Why

"Sky" comes from Old Norse "sky," which originally meant "cloud," not the vault of heaven itself — Old English already had its own native word, "heofon," for the sky in the modern sense, and it was only after Norse settlement in Britain that "sky" gradually took over that broader meaning, pushing "heaven" toward its now more specifically religious sense. Because a consonant, k, sits right before that final y, the same swap kicks in — y becomes i, then -es is added — giving "skies" instead of "skys."

This semantic swap, where a borrowed word for "cloud" ended up meaning the whole sky while the native word for "sky" narrowed to mean specifically the religious afterlife, is a striking example of how Old Norse vocabulary reshaped everyday English during centuries of Viking-era contact, well beyond the more famous cases like "sky" replacing "heofon" for the literal, physical meaning.

Usage note

"Skies" appears often in weather and poetic writing to suggest a broad expanse or varying conditions across a wide area ("cloudy skies," "sunny skies ahead"), while the singular "sky" is more common when referring to the sky as a single unified backdrop overhead.

This particular semantic swap, "sky" edging out native "heofon" for the everyday physical meaning, happened gradually over the Middle English period, and by the time of Chaucer, "sky" had firmly displaced the older word for ordinary weather-related purposes, leaving "heaven" to specialize almost entirely in religious contexts. "Skyline," "skyscraper," and "skylight" are all English compounds built directly on "sky" once it had settled into its modern meaning, treating the word as a productive building block for describing height and visibility.

Common real mistakes

The usual consonant-plus-y misspelling, "skys," is the error to avoid; beyond that, there's little genuine confusion, though some writers overuse the plural "skies" in weather forecasts where the singular would read more naturally. A separate, purely stylistic point is that literary and poetic writing leans on "skies" far more heavily than everyday speech does, since the plural carries a slightly more evocative, sweeping quality than the flatter singular "sky."

The wider pattern

"Sky" follows the identical consonant-plus-y rule as "fly" and "spy," and its Old Norse origin as a word originally meaning "cloud" is a genuinely distinct kind of linguistic history from the Latin- and French-derived words that dominate much of this word family.

Examples

• Clear skies are expected across the region this weekend.
• The painter captured the changing skies over the harbor.
• Stormy skies rolled in just before the game began.
• Photographers waited for the perfect sunset skies.
• Pilots reported turbulent skies over the mountains.
• The forecast predicted partly cloudy skies through Friday.
• Northern skies are famous for their dramatic auroras.
• The festival was rescheduled due to threatening skies.
• Travelers marveled at the star-filled desert skies.
• Gray skies lingered over the city for most of the week.
• Meteorologists tracked the changing skies throughout the storm.
• Artists have long been drawn to painting dramatic skies.
• The balloon festival drew crowds eager to watch the skies.
• Wildfire smoke turned the skies an eerie shade of orange.
• Kite festivals fill the skies with color every spring.
• The observatory tracks meteor showers across clear night skies.
• The eclipse drew crowds to watch the darkened skies.
• Stargazers prize the clear desert skies for viewing.
• The children pointed out shapes in the drifting skies.
• Pilots watched the skies closely before the storm warning.
• The photographer waited weeks for the right skies.
• The drone captured footage of the skies above the canyon.
• Farmers watched the skies anxiously during the drought.
• The festival timed fireworks to light up the night skies.
• Campers marveled at the star-filled skies far from the city.
• The forecast promised clear skies for the weekend hike.