What Forecast Should I Use?

One of the most pressing questions regarding weather is what forecast to use. In this age of social media and widespread internet access, there are so many different forecasts to choose from. This blog will attempt to explain which forecast to choose!

My go-to site to begin choosing a forecast is Forecast Advisor. This handy site shows the accuracy of multiple forecasts over the previous month and previous year. Below is Forecast Advisor's accuracy scores for Seattle in 2020.

The Weather Channel and Weather Underground had the highest accuracy score, over 86%. AccuWeather came up just behind at 84%. Notice that the NWS forecast came in at 78.6%, about 8% below the leaders, showing that just because it is run by the government, it isn’t the most accurate forecast available, though it is still a good choice.

Now let’s see how these trends verified last month. Below are the Forecast Advisor scores for Seattle in August.

Weather Underground and The Weather Channel take the cake again, with scores around 84%. Wetter, a German company, came in third. Notice that the NWS came in with a score of 72.5%.

If you were wondering how the accuracy scores are calculated, Forecast Advisor says in their FAQ page that “The overall accuracy percent is computed from the one- to three-day out accuracy percentages for high temperature, low temperature, icon forecast precipitation (both rain and snow), and text forecast precipitation (both rain and snow). Temperature accuracy is the percentage of forecasts within three degrees. Precipitation accuracy is the percentage of correct forecasts. The forecasts are collected in the evening.”

So, what forecast should you use?

The accuracy scores suggest using Weather Underground or The Weather Channel. These companies, both owned by IBM, have a similar forecasting algorithm that has proven to be accurate over the past few years, with consistent ratings of 80+%.

These algorithms take many things into account when making a forecast. Some things include current, future, and historical conditions and weather predicted by multiple forecast models. 

You can download the Weather Underground and The Weather Channel apps on the iOS App Store and the Google Play Store. You can also find these sites on the web, at wunderground.com and weather.com.

Generally, any forecast with 75-80%+ accuracy will give you a good idea of what conditions to expect. However, if you’re able to use the most accurate forecast, do so. It’ll give you the best idea of what to expect, especially regarding temperatures and precipitation.