this

diesmal

Refers to the present occasion or instance.

Bezieht sich auf die gegenwärtige Gelegenheit oder den aktuellen Fall.

Refers to the morning of the current day.

Refers to the current or immediately approaching afternoon.

Refers to the current or immediately approaching evening.

Refers to the current or immediately approaching summer season.

diesen Winter

Refers to the current or immediately approaching winter season.

Bezieht sich auf den aktuellen oder unmittelbar bevorstehenden Winter.

Refers to the current or immediately approaching spring season.

Refers to the current or immediately approaching fall season, especially in American English.

Refers to the current or immediately approaching autumn season.