What's the difference between "period" and "time"? Is it more correct to say "it rained at the right time" or "the rain happened during the right period"?

Logically if you're a farmer raining at MM YY DD HH MM SS (a specific time) is useless. You need it to rain over months for a couple hours in a patchy way non-continuous period.

Does "time" refer to an indefinite period or a specific quantum mechanical atom flashing?

  1. the indefinite continued progress of existence and events in the past, present, and future regarded as a whole. "travel through space and time"
  2. a point of time as measured in hours and minutes past midnight or noon. "the time is 9:30"

Time does refer to either a specific point or a bunch of indefinite infinite stuff, so according to this "it rained at the right time" is logically incorrect.

  • 1
    The preposition "at" is not used with periods. "At" suggests point in time.
    – fev
    Commented Sep 16, 2023 at 6:21
  • Have you looked in a dictionary? Time can be used in a lot of different ways. (Also, period is more formal than time, which is universal, so consider that.)
    – Stuart F
    Commented Sep 16, 2023 at 8:15
  • With your variants, the second one sounds likely (though not absolutely guaranteed) to be referring to an extended period ... the monsoon season, say. You wouldn't use it for instance after 'The sun was out while we had our picnic; the weather held up nicely while we ate.' Commented Sep 16, 2023 at 13:41
  • A time is one time. A period is the interval between two times. Commented Sep 16, 2023 at 21:32
  • 1
    Weather Vane's comment is over-simplistic. One sense of 'time', as Peter says, refers to the interval between two points in time. Commented Sep 20, 2023 at 15:44

3 Answers 3


“A time” can refer to a period of time, as in “I was overseas for a time last year”. See under time noun (period) in Cambridge dictionary.

“The rain happened at the right time” is quite correct and understandable.

  • 2
    I understand "at the tight time" as "at the right point in time" because of the preposition "at".
    – fev
    Commented Sep 16, 2023 at 6:22
  • But "the baby was born at the right time" is correct even though the "right time" and the birth process both occupy time periods, not instants. We understand that our time statements are not unrealistically accurate. We understand that "at the end of the 19th century" does not mean "at the end of the last second of the year 1900". Scientists sometimes make this explicit by stating the possible errors in time (and other) measurements.
    – Peter
    Commented Sep 16, 2023 at 8:24

Both time and period(s) are possible and idiomatic.

For a crop to grow it needs periods of rain throughout the growing season.

Newly planted seeds need rain to germinate, and so the rain must come at the right time.

A period usually refers to a "stretch" or span of time, whereas time can refer to a specific moment, as in "the right time", or a span of time as in "a long time".


I've the sense that "period" refers to a discrete time subset like in sports: hockey, basketball, etc.

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    – Community Bot
    Commented Sep 20, 2023 at 15:18
  • 1
    That's only one of the ways in which period is used. You also have geological periods, periods at school, periods in art history, and generic periods of time.
    – Stuart F
    Commented Sep 20, 2023 at 17:54

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