Learn Swedish: Vi bygger inte cykelstället till våren. - We are not building the bicycle rack for the spring.

In Swedish, when you want to refer to the very next upcoming season, you use the preposition till followed by the definite form of the season. So till våren specifically means "this coming spring" or "by next spring".

Does till våren mean the exact same thing as i vår?

They are very similar, but they have slightly different focuses. I vår simply means the action takes place sometime during the spring. Till våren carries a sense of a deadline or a target, meaning the bike rack is not being built in time for or by the spring.

The sentence is about the future, so why use the present tense bygger instead of ska bygga?

Just like in English, Swedish often uses the present tense for future events that are planned or scheduled. Because the time marker till våren clearly places the event in the future, you don't strictly need a future auxiliary verb like ska or kommer att.

How do we know the gender of a compound word like cykelstället?