How Does the Time to Expiration Affect the Vega of an Option?

Vega increases as the time to expiration increases. Options with a longer time to expiration have a higher Vega because there is more time for the implied volatility to affect the option's value.

A change in volatility has a greater potential impact on a long-dated option's final payoff than on a short-dated one. Vega is typically highest for ATM options with 3-6 months to expiration.