Set a Coupon Expiry Date and Time In WooCommerce

1. Go to your WordPress Admin panel. Click on Marketing > Coupons.
2. Create a new coupon or open an existing one.
3. Under the “General“ tab, choose the discount type, coupon amount.
4. Under “Coupon expiry date”, click on the box to open the date selector and pick a date.
5. Now under “Coupon expiry time“, click on the box field to open the time selector. Use the slider to set hours & minutes or directly type the time in the box and click on Done. You’ll have to set the time in the 24-hr format.
6. Set other usage and restrictions as required and Publish/Update your coupon.

Important to know

1. Coupon expiry time will work in combination with the Coupon expiry date. If the Coupon expiry date is not set, then the coupon expiry time will not be considered for validation.
2. The field “Coupon expiry time” will follow the local time of your website shown under Settings > General > Timezone.

Reference Blog
Set a Coupon Expiry Date and Time In WooCommerce