How accurate are my forecasts?

How the grading works

Before each day I log a high, a low, a chance of rain and a rain total for six Ohio cities. The site saves it with the time I saved it, and it can't be edited after that. If I withdraw one before its date, it's listed below as withdrawn. Once its date arrives, it can't be withdrawn at all.

Only my own numbers are graded. A new forecast starts filled in with the National Weather Service forecast, and I change the numbers I forecast myself. When it's saved, the site records whose each number is: mine if I changed it from the NWS forecast saved at that same moment, or marked it as mine; the NWS's if I left it alone. Numbers I left as the NWS forecast stay on the record and are marked, but they never count for or against me. The comparison with the NWS uses only the numbers that are mine.

Forecasts I logged before October 3, 2026 have no record of whose each number was. They stay on the record and are graded the same way, but a number counts as mine only if it differs from the NWS forecast saved with it. Where no NWS forecast was saved to compare (and for every rain total, because the old NWS rain figure was a stand-in), the number is left out, and the count of numbers left out is shown below the results.

At that same moment the site also saves the National Weather Service forecast for the same place and day (from api.weather.gov), and the National Blend of Models, the computer-model blend forecasters start from. All three get graded on the same days against the same observations.

What actually happened comes from the National Weather Service's daily climate report for each city's airport, the final one issued after the day ends, midnight to midnight standard time. Each result below links the report it came from. If a final report never shows up, the station's record in ACIS (the regional climate centers' database) is used and named instead. Missing data is left out and counted. It's never filled with zero.

• Average miss: how many degrees off my high or low was, on average.
• Within 3°: how often I was within 3°F.
• Bias: whether I run warm (+) or cold (−).
• Rain score (Brier score): how good my rain chances were. 0 is perfect, and saying 50% every day would score 0.25. A trace counts as dry; it has to measure 0.01" or more.
• Lead day: Day 1 means I issued it the day before. Same-day forecasts are graded but kept out of the headline numbers.