Have you ever noticed that the weather forecast seems to be a mistake an awful lot? There are many grounds for this; most of which could be summed up as “predicting the weather is incredibly hard,” but here are three more detailed explanations as to why weather forecasters can base their predictions on science, but still be so wildly wrong so often.
Weather Forecasters Depend on a Huge Amount of Data
Accurate weather forecasting can only happen if there is a lot of data to back it up. There are 11,000 observation stations spread all over the world measuring the temperature, air pressure, wind speed, humidity, the direction of the wind, rainfall, and some other conditions to try to predict the weather. In addition to the static stations, there are aircraft, weather balloons, satellites and even merchant ships measuring that stuff on the move.
Computers combine that data to try to predict the weather – but if you stop and think about it, tens of thousands of ‘weather stations’ is a small number of stations to cover the entire world. Predictions are getting better as we get access to more data and build more accurate models – but we’re still a long way from being entirely accurate.
Short Term Predictions are Hard
Another thing that you have to remember is that we’re using scientific models to predict what will happen, and in the medium term those models hold up pretty well. Most people don’t want to know whether “it will rain heavily this week,” they want to know whether they can walk to work or whether they should hop in the car because it will rain in the next hour. The models we have right now, combined with the data that we have access to right now, simply isn’t up to predicting on that sort of scale.
Weather is Always Moving
The other thing that makes it hard to predict the weather is that the weather patterns are always moving. We might know that those pressure patterns are going to cause high winds – but if those patterns are themselves drifting across the map, we don’t know exactly where those trends will hit. That’s why, when the weather forecasters predict snow, you might be sitting at home looking out at a bitterly cold, windy day with lashing rain, but your friend in the next town across could be enjoying spectacular, beautiful day with peaceful snow falling from the sky.
It’s not that the weather forecast was WRONG, just that it was a few miles out.
As humans, we notice patterns even if they are just pure coincidences, and we see when things affect us more than we notice when things change other people. This means that we will pick up on the times that the weather forecast was wrong and we overheated or got soaking wet because we trusted the broadcast. We overlook the other days of the year when the weather is neutral, and we didn’t pay attention to the forecast at all because “T-shirt weather” and “Slightly warmer t-shirt weather” aren’t enough of a difference for the average person to even know whether the weather forecast was right or wrong.
Once you get used to that idea, and you start paying more attention to the weather forecasts, you will understand that the science we have right now is good when it matters. We can predict tropical storms and hurricanes and give people time to prepare. Yes, there is room for improvement, but we are still in a better position than we used to be even just a few years ago.