Hours Were Once Longer in Summer Than in Winter
An hour is a unit of sixty minutes. Before mechanical clocks its length changed with the seasons.
An hour is a period of sixty minutes, one twenty-fourth of a day. For most of history hours were not fixed: daylight was divided into twelve parts whatever the season, so a Roman summer hour ran to about seventy-five minutes and a winter one to about forty-five. Only mechanical clocks, which could not vary, forced hours to become equal. The division into sixty comes from Babylonian arithmetic, which counted in sixties rather than tens.
- Sixty minutes. *An hour's walk.*
- A particular time. *At this hour.*
- Hourly — every hour. *Hourly.*
- Silent H. *An hour.*
- Greek — *hora*, a season or time. *The root.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | hour | An hour. |
| Plural | hours | Hours. |
| Adjective | hourly | Hourly. |
| Compound | hourglass | An hourglass. |
| Greek | hora | A season. |
- The journey took an hour.Time.
- Roman hours varied by season.History.
- The H is silent.Pronunciation.
Why sixty minutes
- Babylonian mathematics used base sixty
- Sixty divides evenly by 2, 3, 4, 5, 6, 10, 12, 15, 20 and 30
- That made fractions easy without decimal notation
- The same system gives 360 degrees in a circle
- It survives in time and angle but nowhere else in daily life
Old French *ure*, from Latin *hora*, from Greek *hora*, a season, time or period.
Were hours always the same length?
No. Daylight was divided into twelve parts regardless of season, so summer hours were longer than winter ones until mechanical clocks fixed them.
Why are there sixty minutes in an hour?
From Babylonian base-sixty arithmetic. Sixty divides evenly by many numbers, which made fractions easy before decimals.