How to Predict If It Will Snow!

Snow. A wonderful, beautiful natural phenomenon. The way it quietly sits on snow covered trees and the way it gracefully falls to the ground. Everything is beautiful about snow except predicting when it is going to snow. Meteorologists have spent years trying to predict exactly when it is going to snow and how much. In this article, I’m going to give you a nice easy way to predict how likely it is to snow.

First, you are going to check your weather forecast provider for the chance of snow on a certain day. Once you have the percent chance for how likely it is to snow on a certain day, you can start calculating.

Take the example that the weather forecast says there is a 50% chance of snowing on Monday and a 30% chance of snowing on Tuesday. Since we need to know how likely it is to snow on at least one of these days, we might try to use complementary counting. Complementary counting is subtracting the probability that an event does not occur from one to find the probability of an event occurring. For this example, since there is a 50% chance of it snowing on Monday, there is also a 50% chance of it not snowing on Monday. By the same logic, there is a 70% chance of it not snowing on Tuesday. Now, to find the probability of it not snowing on both days, multiply the chance of it not snowing on Monday by the chance of it not snowing on Tuesday. Therefore, the chance of it not snowing on both days is 35% (1/2*7/10). Now, since we want to know if it will snow at least once, by complementary counting, the chance of this is 100%-35% so the chance of snow on at least one of these days is 65%.

This logic can be extended to more complicated topics. For example, assume that there is a 20% chance that it will snow enough for school to be cancelled. Therefore, the chance that school will not be cancelled on Monday is 50% + 80%*50% = 90%. Also, the chance that school will not be cancelled on Tuesday is 70% + 80%*30% = 96%. It follows, by the same reasoning as earlier, that the chance that there will be school on both days is 90%*96% = 86.4%. Finally, by complementary counting, the chance that school gets cancelled on at least one of the two days is 100%-86.4% = 13.6%.

This concept can also be applied to more than just two days. Just keep multiplying the chances of no snow together. As you might notice, the chance of snow becomes higher and higher as you add more days. This is because the chance for none of them to have snow becomes more and more unlikely. Have a great snow-filled winter!