No Two Parks Are Equal
Baseball is the only major sport whose field dimensions differ from venue to venue. Fences vary in distance and height, foul territory ranges from cramped to vast, and altitude and climate change how far a ball travels. A park factor quantifies how much a stadium inflates or suppresses runs relative to a neutral average.
The Famous Extremes
Coors Field in Denver sits a mile above sea level; thin air lets the ball carry, making it the most run-friendly park in the league. Pitcher-friendly parks with deep fences and heavy marine air, by contrast, can erase a hitter’s power almost entirely.
Weather on Top of Geometry
Wind direction and temperature ride on top of the fixed dimensions. A ten-mile-per-hour wind blowing out can turn a warning-track out into a home run; the same wind blowing in does the reverse. Cold air is denser and suppresses carry.
How Ra Adjusts
Every projection is run through the specific park and the day’s forecast before a verdict is locked. A total that looks high in the abstract may be perfectly normal once you account for a small ballpark on a warm night with the wind blowing out.