How did Poland avoid the BLACK DEATH?

The black death was an urban syndrome. People living in rural circumstances were not affected nearly so much. I know the average monk writing about it thought cities and towns were the whole world, but believe or not, farmers are people too.

Poland wasn't actually "spared", it was merely less affected than the rest of Europe. That graphic is incorrect (or rather, incomplete), since a substantial number of both Poland and Milan's population did in fact die of the plague. Their death rates were only "low" in comparison to the rest of Europe. Poland lost about a quarter of its population to the plague (...) Milan's death rate was less than 15%, probably the lowest in Italy save a few Alpine villages.

[M]uch larger areas, such as central Poland ... locations 'off the beaten trail' and not along the more popular trade routes were more likely to be on the lookout for ill travelers, 'foreigners', or perhaps not even be visited by outsiders at all. We believe that it was the exclusion of medieval traders and pilgrims that would significantly account for the lightly-affected Medieval Black Death regions.

The travel times and relative isolation were probably enough to stop most of the spread (explained in comments below) ... Considering peasants were not allowed to travel in those days, most likely the plague was spread by traders, this is why the more dense populations were more affected. With more remote populations kept safe especially since it could kill within 24 hrs of catching it probably those infected died before reaching their destination.

It was too cold

This is a myth. It didn't.

Poland didn't avoid it, they suffered as well and lost 25% of the people, mainly because the people lived in isolated communities which the plague didn't get to as people didn't travel into other communities to spread, there were several countries where isolated non traveling communities avoided the plague across the while of Europe

It did not escape entirely, but they had the sense to have strong quarantine rules at their borders,so this softened the amount of germ ridden people who got in.

It didn't.

You're likely looking at a map which ignores their death rate of less than twenty-five percent.

They had a low death rate, not a non-existent one. That lower death rate is a result of Poland not having many cities. The more urban a country was, which Poland decidedly was not, the higher the number of plague cases.

By chance, aided by geography and weather. There were a few other small parts of Europe largely unaffected by the Black Death.

Note also that the borders of Poland have changed many times in history - twice in the 20th century (latest in 1945, when it moved bodily 100 miles west), so make sure that you are reading about the area that you think you are referring to.

Because they were isolated from the seaports in the Mediterranean; Aegean; Black Seas and Atlantic Ocean.

I don't think that there were some special reasons. Back in those times, Poland was still some kind of "frontier" to the rest of Europe, lying in the off. There wasn't much traffic and not much exchange. Maybe it's true that the end of the Black Death came when the virus mutated and lost its power. It's easily possible that it didn't reach Poland before that last stage.