Does Warm Weather Create Better Players?

My high-school-aged son sits at home yet again. Why? Because another of his baseball games has been canceled due to the wet and cold Ohio spring, and my thoughts turn again to our days playing baseball in Florida. Before we moved to this less-agreeable northern climate, it was a rarity to have a game canceled due to weather. Not only that, but games were scheduled year-round, which of course meant more baseball on the calendar. This situation reminded me of the familiar equation known to baseball fans:

Good weather leads to more playing.
More playing means better players.

But is this true? After all, it’s well-known that the best player in baseball, Mike Trout, is from cold-weather New Jersey. Many quickly point to the fact that California, Texas, and Florida are at the top of the list for states with the most MLB draftees, but they’re the three most populous states. Perhaps proportionally they don’t stack up to colder states after all.

I decided to look at the data from the last two drafts — 2017 and 2018 — to see if there is a relationship between a state’s average temperature and how well its players do in the draft. Do warmer-weather states really produce more MLB draftees than average?

To do this, I first gathered population data from each state to determine what percentage of the overall US population it contains. Then I did the same for each states’ MLB draft population. Finally, I compared those two figures and determined the percentage difference between their population proportion and their draft proportion. I call this figure the “Draft Difference”.

For example, let’s say State X makes up 10% of the US Population, but the State X’s draft class makes up only 8% of the overall class. Its Draft Difference is calculated as:

(Draft-Population)/Population = Draft Difference

In this case,

(8-10)/10 = -.20 = -20%

A state with 10% of the US population should, all things being equal, contribute 10% of all players in an MLB draft. But, in this case, State X did 20% worse than should be expected just from its population size.

After I came up with the Draft Difference for each state, I found the average annual temperature for each state.

Then came the actual check of the relationship. I calculated the Pearson Correlation between the Draft Difference and the Avg Temp: if warmer weather means better players (and thus more draftees), then the correlation should be near 1. If, however, warmer weather somehow meant worse players, then the correlation would be negative and closer to -1.

Here are the results for 2017 and 2018, along with a scatter chart to show the relationship:

2017: 0.76

2018: 0.74

Full data can be found here.

Anything over 0.6 demonstrates at least some correlation, and anything over 0.75 is a strong correlation. Although 2018 is just below 0.75, I think it’s safe to say that there is a definite correlation between a state’s temperature and the strength of the baseball players it produces.

Quick aside: how did California, Texas, and Florida do?

2017:

• California: 28% over population size
• Texas: 12%
• Florida: 93%

2018:

• California: 3%
• Texas: 0%
• Florida: 71%

Of the “Big 3” states, it appears Florida is the real powerhouse when it comes to producing MLB Draft picks in greater proportion than can be expected from its population size.

Now, a few caveats and disclaimers.

First, there is the fundamental question, “Where is someone from?” My son was born in Maryland, played Little League in Florida, and now plays high school ball in Ohio. Perhaps he’ll end up playing college baseball in North Carolina. So where is he from? The draft database I used from Baseball America typically assigns the state where the player last went to school, whether high school or college. So if Player Y went to high school in Maine, then played in college in Florida before being drafted, he counts under Florida numbers.

And that brings us to another point. Does warmer weather produce better players, or are better players attracted to warmer weather? In the case of drafted high school players, the role warmer weather plays in development is more clear. After all, that’s where they’ve played during their development and recruitment process. But what if solid players from around the country flock to warm-weather colleges because they know they’ll get a longer season in which to train (and because so many solid players do that, they also get better competition)? Thus colleges in warm-weather states end up with better baseball programs through this process, continuing the cycle of attracting better players. This demonstrates the difference between correlation and causation: just because Draft Difference and Avg Temp are correlated doesn’t mean one caused the other.

Finally, I didn’t consider the draft ranking of each player; a first-round pick is equal to a 40th-round throw-in. I don’t think that is a problem since even to be drafted at all means you are the best of the best in the country — one of the top 1,200 players out of a pool of hundreds of thousands. The difference between first and 40th-round picks is less than between a 40th-round pick and most non-drafted baseball players in the country. You have to be good to be drafted.

Whatever the reason, however, it’s clear that MLB draftees are indeed more likely to hail from — or go to school in — states with warmer climates. Just don’t tell my son, or he’ll be begging us every day to move back to Florida.