After looking at the effect of weather on MLB pitchers and the baseball odds, we now turn our attention to the hitters, and how different conditions can affect their performance.
Jason's 2015 record as of June 10: 28-19, plus-8.84 units ML; 0-3, minus-3.30 units Total
On the heels of our Pulitzer-ignored article on weather and its impact on baseball pitchers, it's time to look at the other side of the coin and see how the hitters are affected by different conditions. Naturally, if pitchers get more strikeouts in colder weather, hitters are going to strike out more – it's the same coin, after all. But we're trying to keep the two sides as separate as possible for now. We'll combine them later when we look at the overall effect of weather on the baseball odds, specifically with the MLB totals.
Blow Wind Blow
Once again, let's start with the most obvious element: the wind. Once a baseball comes flying off a bat, it goes into the air, where the wind will either push or pull it in a certain direction – or neither, or both. Wind can be tricky like that, especially when it's circulating inside a baseball stadium with all those irregular nooks and crannies.
One of the most important things to look at when you're making your MLB picks against the total is how much impact the wind has at each specific stadium. Stats are freely available on the Interwebs to show you how the totals are doing when the wind is blowing in a certain direction at a certain speed; for example, as we go to press, the OVER is 11-4 at Dodger Stadium this year when the wind is blowing out to right field at up to 10 mph, compared to 1-4 when blowing across the diamond from left to right.
Eight Miles High
While a 15-mph gust of wind can turn a deep 400-foot fly ball to center into a 445-foot home run, something as simple as elevation can have nearly the same effect even on a calm day. As we said in our look at pitching in warm or cold weather, air density plays a significant role; colder air is denser, so pitches slow down and break more. Naturally, it'll be the same for hitters in cold weather – we'll get to that in a moment.
For now, let's stick with elevation. Coors Field in Denver (elev. 5,200 ft.) was a notorious hitter's park because of the thin air, so notorious that they started using a humidor in 2002 to store the baseballs and make them a little squishier. Otherwise, there's about a five-percent increase in the flightpath of a ball hit at Coors Field compared to a ballpark at roughly sea level, like Fenway Park or Yankee Stadium. That's enough to turn a 400-foot deep fly into a 435-foot homer.
Hot to Trot
Okay, now let's get back to the temperature. Scott Lindholm at Beyond the Box Score did a fine job last year of breaking down the numbers at Baseball Reference and showing how batting average and home run rates increased as the temperature rose. Batting averages went from .251 when it's 40 degrees or below, to .277 when it's over 90. Home runs shot up from .023 per at-bat to .034.
Again, much of this is because there's less break on the pitches when it's warm out. But it's also because the air is less dense and the ball travels farther when the hitter makes contact. Combine these factors, and you naturally get a higher rate of OVER results the warmer it gets. The betting market does cut into the profitability of this play – there are plenty of savvy bettors out there who are watching the weather reports and moving the MLB odds when they make their MLB picks. But there are also enough “squares” in the market who are betting blindly and making this angle worth pursuing. Just don't blame the weather reporter if things don't turn out right.