There isn't a specific period when all the stars suddenly get brighter. However, there are a few factors that can make stars appear brighter at certain times:

* Earth's Position: As Earth orbits the sun, our perspective on the stars changes. This means that some stars might appear brighter at certain times of the year due to their position relative to Earth.

* Atmospheric Conditions: Clear nights with little light pollution and minimal cloud cover will make the stars appear brighter.

* Variable Stars: Some stars naturally change in brightness over time. These are called variable stars, and their brightness can fluctuate significantly.

* Supernovae: When a star explodes as a supernova, it can become incredibly bright, even outshining entire galaxies for a brief period. However, this is a rare event.

In general, the overall brightness of the stars in the night sky remains relatively consistent.

Let me know if you'd like to know more about any of these factors!