Is Hochsaison der, die or das?

The correct German article for Hochsaison is die. The noun Hochsaison is Feminine. So you always say: die Hochsaison. Learn the article together with the noun — German nouns don't follow predictable gender rules most of the time.

The plural of Hochsaison is: die Hochsaisons. In the plural, every German noun takes the article "die". So: die Hochsaisons. Example: ein Hochsaison → zwei Hochsaisons.

Correct: die Hochsaisons. The form "die Hochsaisons" is wrong. The plural of die Hochsaison is die Hochsaisons. In the nominative plural, you always use the article "die".

die Hochsaison follows the four German cases. Nominative: die Hochsaison, Accusative: die Hochsaison, Dative: der Hochsaison, Genitive: der Hochsaison. In plural: die Hochsaisons / den Hochsaisons. Learn these forms together with the noun.

The genitive singular of die Hochsaison is: der Hochsaison. The genitive plural is der Hochsaisons. German uses the genitive to express possession or belonging. Example: die Farbe der Hochsaison.

The dative plural of Hochsaison is: den Hochsaisons. In German, dative plural nouns usually end in "-n". So you say: "mit den Hochsaisons". Use this case after prepositions like mit, von, bei, zu.

Hochsaison is a noun and must be capitalized in German. You'll find example sentences above for each case. The article die stays the same in nominative singular but changes in other cases. Practice declension in your own sentences.

Yes, Hochsaison is a noun (also called a substantive). German nouns are always capitalized. The article for Hochsaison is die. Every German noun has a fixed article you must memorize.