Вечером я собираюсь поработать всего час, а потом отдохнуть.

In the evening I am going to work for only an hour and then rest.

Breakdown of Вечером я собираюсь поработать всего час, а потом отдохнуть.

• я: I
• вечер: the evening
• а: and
• отдохнуть: to rest

Questions & Answers about Вечером я собираюсь поработать всего час, а потом отдохнуть.

What case is вечером, and why does it mean “in the evening / tonight” without a preposition?

Вечером is the instrumental case of вечер (evening).

Russian often uses the instrumental case without a preposition to express time when, especially with parts of the day:

• утром – in the morning
• днём – in/at the daytime
• вечером – in the evening
• ночью – at night

In everyday speech, вечером usually means this evening / tonight if we’re talking about today, unless context clearly points to another day.

Is there any difference between вечером and сегодня вечером?

Both can mean this evening / tonight, but there is a nuance:

• вечером – usually understood as “this evening” from context, a bit shorter and more neutral.
• сегодня вечером – literally “this evening (today)”, more explicit; you’d use it if you want to be very clear it’s about today, or to contrast with another day (e.g. вчера вечером, завтра вечером).

In your sentence, Вечером я собираюсь… will normally be understood as “This evening I’m going to…”, unless the context says otherwise.

What exactly does я собираюсь mean here? How is it different from just using a future tense like я поработаю or я буду работать?