I have a secret theory. Don’t judge too quickly. Hear me out. Pittsburgh skies are filled with clouds, darkness, and rain. Yinzers are just use to depressing weather. Thus our sports teams like the Pirates should perform better in rain.

Luckily, we have data…

Ever The Dark Knight Rises Put Bane in the Grey Skies of Heinz Field.

In a list compiled by weather scientist Brian Brettschneider, Pittsburgh ranks 2nd place for the Dreariest Cities in America. The three measurements he used to calculate the scores were cloudiness, precipitation, and wet days. Hell, 84% of Pittsburgh Days have at least 1/4th of cloud cover.

If sports teams practice in rainy conditions, hypothetically they should be better suited to play in them. I did what any journalist worth the grain of salt would do: I asked an expert.

I reached out to Sophia Tupolev-Luz, Chief of Staff of ClimaCellClimaCell is a weather data company with new tricks to track rain block by block, minute by minute, using wireless communications networks. They’ve raised $4.95M in funding so far. Don’t worry. They’re based in Boston, so they’ll dampen any local bias I may have.

PNC Park in front of a Pittsburgh Skyline
PNC Park in Pittsburgh, Pennsylvania. (Foo Conner/Jekko).

The question: Do weather conditions predict outcomes for Pirates games at PNC Park? 

The Method.

ClimaCell extracted all the dates of the Pirates’ home games at PNC Park, and marked them with a W or L. There were 1002 home games that could be analyzed from 2007–2017, excluding postponed games and ties.

Where Did the Weather Data Come From?

PNC Park to Allegheny County Airport

We used the NOAA historical database which includes temperature, humidity, and precipitation. The closest monitoring station to PNC Park, the Pittsburgh Pirates home stadium, is at the Allegheny County Airport (KAGC) 7.3 miles away. You probably know this airport because it’s where the Pittsburgh Aviation Animal Rescue Team is located. They transport animals from overcrowded shelters to less crowded ones where dogs can find their forever homes.

For our example here, the spatial resolution of this data is one data point. KACG currently reports data every 5 minutes, which is much more frequent than the norm of once every 15–60 minutes. This means the temporal resolution is 5 minutes.

Which Seasons Were Analyzed?

Vintage Iron City Light Cans on Display at Bicycle Heaven

Look. I know some of you die hard fans want us to go as far back as 1979, 1971, 1960, 1925, or even 1909… but we really need to limit ourselves to more recent data.

We analyzed Major League Baseball seasons 2007-2017, including spring pre-season and post-season games. Our 2017 data ends on June 18th, 2017 when we began this article. ClimaCell started with a sample of the data set covering the four year period from 2014–2017, then ran the whole 11 year set from 2007–2017. In that time, the Pirates lost 480 home games and won 522.

The Surprising Results: What We Found in the Data.

In the last 11 years, when it rained, The Pirates won 151 games and lost 128. When it was dry, they won 371 and lost 352 games. The winning percentage was actually higher (54.1%) on rainy days vs dry days (51.3%). But wait!

On dates that it rained a lot (over 5 mm accumulation), the Pirates winning percentage was 58.62%!

On dates that it rained a lot (over 5 mm accumulation), the winning percentage was actually 58.62%! The normalized histogram below shows all the data (1002 games) spread out over how many games of each type there were for each level of total precipitation from 1–30 mm. The blue bars show the distribution of losing games by amount of rain or snow, and the orange bars represent winning games. It rained a total average of 11.78 mm when they won and 9.53 mm when they lost.

2007–2017: Normalized histogram of total wins and losses in the data set, per level of precipitation

This was very pronounced in the data set for the last four seasons: the Pirates won more games when precipitation was up to 10 mm.

2014–2017: Non-normalized histogram of number of wins/losses per precipitation accumulation

We Also Looked at Temperature:

We also looked at the average temperature during Pirates games. Winning games averaged 68.86 F and losing games 68.09 F. In the chart above we can see the typical cool springs, hot summers, and red cardigan weather for falls. Overall, The Pirates lost a bit more often in average temperatures of between 50–68 Fahrenheit.


Couple looks over to PNC Park from the Roberto Clemente Bridge filled with Love Locks.

Now we know that rain makes a difference. Before you say, “Hold my I. C. Light,” and head over to Rivers Casino, let’s talk about money…

Stadiums themselves have a vast network of ground crew that handle everything from bobble heads to serving your beer. Millions are lost each season from miscalculated rain delays and cancellations. Major League Baseball did not have an exact estimate on hand when I reached out to them.

One of the reasons I contacted ClimaCell was for more accurate data. Imagine being able to change your bets as you watch the rain roll in real time. Or knowing when to wrap up tailgating before the grill is a grey slush of ashes. Or simply skipping a rain delay.

tl;dr: If you love the Buccos, cheer for rain. If you play the Buccos, demand rain delays. 

If you have a weather theory for another sports team,
Head on over to Facebook and comment on the thread.
We might do the next article on it.

Editors Note: This article is ad-free. No monies were exchanged for this article. Jekko often will seek out data help from thought leaders and scientists, which ClimaCell is for weather.