How Does Time to Expiration Affect an Option’s Vega?

Time to expiration has a significant impact on an option's vega; specifically, vega is higher for options with longer maturities. The more time an option has until it expires, the more opportunity there is for the underlying asset to experience a large price swing.

This increased potential for movement makes the option's value more sensitive to changes in the market's expectation of volatility. Conversely, as an option approaches its expiration date, its vega decreases because there is less time for volatility to have an impact on its outcome.