Weather forecast accuracy details for Grafton, Illinois

These are 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.

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Weather Forecast Accuracy Data Last Month (September)

Provider High Temp Low Temp Icon Precip Text Precip Overall
Weather Underground   92.22% 70.00% 90.00% 90.00% 85.56%
AccuWeather   90.00% 67.78% 87.78% 85.56% 82.78%
The Weather Channel   91.11% 71.11% 83.33% 83.33% 82.22%
Foreca/Vaisala   81.11% 67.78% 88.89% 88.89% 81.67%
AerisWeather   87.78% 62.22% 83.33% 83.33% 79.17%
NWS Digital Forecast   86.67% 60.00% 73.33% 73.33% 73.33%
Wetter   66.67% 41.11% 86.67% 86.67% 70.28%
OpenWeather   65.56% 55.56% 77.78% 77.78% 69.17%
World Weather Online   51.11% 43.33% 72.22% 72.22% 59.72%
Persistence   36.76% 33.80% 63.24% 63.24% 49.26%
Weather News   78.89% 28.89% 86.67% 0.00% 48.61%

Weather Forecast Accuracy Data Last Year (2020)

Provider High Temp Low Temp Icon Precip Text Precip Overall
The Weather Channel   72.07% 70.70% 86.63% 86.63% 79.01%
Weather Underground   72.07% 70.70% 86.14% 86.14% 78.76%
AccuWeather   70.21% 71.19% 82.50% 81.81% 76.43%
Foreca/Vaisala   64.70% 68.44% 83.19% 83.19% 74.88%
AerisWeather   67.16% 65.09% 77.38% 77.38% 71.76%
NWS Digital Forecast   67.44% 67.84% 73.97% 73.97% 70.80%
Wetter   45.30% 53.12% 80.71% 80.71% 64.96%
OpenWeather   41.99% 50.93% 75.61% 75.61% 61.04%
World Weather Online   46.84% 48.62% 71.10% 71.10% 59.42%
Persistence   29.95% 32.30% 62.31% 62.31% 46.72%
Weather News   54.00% 47.87% 72.54% 0.00% 43.60%

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The data here is calculated from forecasts and observations collected and analyzed by ForecastWatch. If you would like more information about the methods, scientific approach, and the quality controls employed to ensure the data and analyses are of the highest quality, please read this overview.

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