When combined, the characters literally translate to “Time comes, fortune turns.” This creates a powerful image of destiny or fate as a wheel. You may be stuck at the bottom for a while, but with patience, the right time (`时`) will eventually arrive (`来`), causing the wheel of fortune (`运`) to turn (`转`) in your favor.
The connotation is always positive and hopeful. As a chengyu, it adds a bit of literary elegance to a sentence but is common enough to be used in everyday conversation.