Explaining "One swallow does not make a summer"
What does it mean?

The phrase means that a single occurrence or sign does not necessarily indicate a larger trend or truth. It suggests that one positive event is not enough to assume that the situation is favorable overall.
Tone
Pragmatic
Origin
The phrase is derived from a saying attributed to Aristotle in "Nicomachean Ethics," reflecting the observation that the appearance of a single swallow does not mean that the summer season has arrived.
Examples of usage
- Just because the stock market went up today, don't assume it's going to keep rising. One swallow does not make a summer.
- She got an A on her first test, but one swallow does not make a summer; she needs to maintain good grades throughout the semester.
- Years ago, we closed a big deal early in the year, but learned that one swallow does not make a summer when the next few months were slow.