Bill James has a new statistic, temperature gauge.

The statistic, which starts at room temperature — 72 degrees — goes up or down depending on what a hitter does at the plate over a period of time. For example, if a hitter hits a home run, his temperature goes up, and he gets hotter. On the flip side, a double play will cool a hitter off considerably.

See a detailed explanation below or watch James explain further in the video below.

Temperature Gauge is a measure of how hot or cold a hitter is using Fahrenheit degrees as the metric. A hitter starts the year at 72 degrees (room temperature), every time he reaches base, it goes up, increasing incrementally with a double, triple or home run. Inversely an out, strikeout or double play decreases a hitter’s temperature.

Fifty percent of the temperature is calculated using the hitter’s last three to four games. Twenty-five percent is the previous three or four games. The other 25 percent dates back to the beginning of the season.  Therefore, the hitter’s most recent performance is the key contributor to how hot or cold he is.