70 Percent Chance of Snow Friday Doesn’t Mean What You Think
I was today years old when I learned something confusing about our weather forecasts. We often hear the weatherman say we have a certain percentage chance of precipitation in their forecasts. Take this Friday for example, it says we have a 70 percent chance for snow and up to one inch. Then, we'll get mad when we don't get any rain or snow. But it turns out the forecast is a bit more complex than that 'certain percentage' they mention. This TikTok video explains it pretty well:
Basically, that certain percentage chance of precipitation is a combination of two other percentages multiplied to get an answer. If the weather man thinks there is a 30 percent chance that 60 percent of the covered area will get rain, he might say there is an 18 percent chance of rain. But he doesn't tell you that he thinks the chances are slim but more than half of the area he's talking about could get drenched. If he's 90 percent certain that only 20 percent of the area will get rain he could again say there is an 18 percent chance. I guess this means that Friday he's 95 percent sure that 74 percent of Twin Falls will see snow? Weather and math are weird.
I thought weather forecasts were pretty vague before and now I think they are even more vague. Unless they break it down into smaller sections of the area they are talking to, you could get surrounded by snow but have none fall on your yard and the weatherman would still be right if he said there's a 90 percent chance of snow.
This also clears up another of my misconceptions, I also thought that the percentage was the amount of time it would be raining during that time frame. But that was just me being wrong again, and since I hate math I'll just keep looking at weather the same as I did before without the complication of multiplication.
Did you know about the math behind a weather forecast?