How long is a Convective SIGMET valid for?

A Convective SIGMET is specifically defined as being valid for 1 hour. This type of SIGMET is issued for significant weather phenomena associated with convective activity, such as thunderstorms, and reflects the immediate and transient nature of these weather conditions.

The validity period is intentionally kept short due to the rapidly changing dynamics of convective weather, which can significantly alter conditions in a short time. Therefore, pilots rely on the current and timely nature of Convective SIGMETs to ensure safety during flight; these reports provide critical information about severe weather that may impact flight operations. Other options, while they may pertain to different types of weather advisories, do not align with the 1-hour validity that characterizes Convective SIGMETs.