one swallow does not a summer make esperantoksi - Sanakirja.org (englanti-esperanto)

Käännös
Sanonnat
1.	unu kukolo printempon ne venigas

One instance of an event (such as the arrival of a single bird) does not necessarily indicate a trend.

[T]hough one swallow does not make a summer, one engagement is apt to make several, and her boys were, most of them, at the inflammable age when a spark ignites the flame.
One swallow does not a summer make, nor one onion a spring garden.
One swallow does not a summer make and one football game doesn't make a season.
Added one Western diplomat: "Aquino's success undoubtedly weakens the Communists' appeal to the so-called mass base. But one swallow does not a summer make."