How Meteorological Conditions Affect Punting and Punt Outcomes

How does weather affect punting and punt outcomes? We know from prior studies that decreasing temperature is associated with reduced accuracy for field goals from the 25-yard line and farther.  Likewise, longer field goals tend be more accurate in the high altitude of Denver.  Regarding punts, there is evidence suggesting wind reduces punt yards. 

In short, we’re using 37,253 or so NFL punts from 2002-16. A weather data set culled from NFL Savant covers only 28,000 or so of those punts, through 2013, or about 75% of the data set. 

Figure 1. Average Punt Yards by Altitude

We can first see in Figure 1 that altitude has a limited effects on punt yards (PY) with the exception of the highest altitudes. The second highest altitude group includes Atlanta and Arizona, which average nearly 1 yard more on punts (p = 0.001; Atlanta is a dome) and Denver averages nearly 3 yards more per punt (p <0.001). This is consistent with findings on field goals. 

I used a generalized additive regression with smoothing splines to examine weather effects on punting. The punt spot (PS), wind (in MPH), temperature (Fahrenheit), and precipitation (%, 0-1) as well as all interactions between the meteorological variables were all fit with splines. I included the categorical variable for altitude instead of a smooth line for altitude because Denver distorts the altitude spline. I suppose I could have transformed the variable, but the laziness vice is king for the day. I also included a variable indicating if the punt was in a dome or open stadium. 

Figure 2. Modeling punt yards as a function of temperature, precipitation, and wind

As shown in Figure 2, weather appears to influence punt distance. Lower temperatures result in shorter punts. Wind appears to be most influential when precipitation is greatest. Maximum precipitation appears to reduce punts by about 3 yards, on average, compared to no precipitation. The influence of temperature is diminished when wind and precipitation increase. That punt distances are reduced in increasingly inclement meteorological conditions is consistent with the existing literature on field goals and punts in the NFL. The effect of the Denver altitude is consistent in this model, but the effect of Atlanta and Arizona is diminished likely because the model accounts for dome conditions. The upper rightmost panel is weird, though, perhaps because having only a few cases with higher wind speed influences this finding?

Figure 3. Punt return yards by altitude

There appears to be negligible effects of altitude on average punt return (PR) yards on punts that were actually returned (R2 < 0.001, that is R-squared not p!); see Figure 3. Not shown is an ecologically meaningless but statistically significant effect of temperature increasing PR yards on returned punts by about 0.13-yard for every 30° increase in temperature. Ah!, the frivolity that emerges from large data sets.

Figure 4. Punt outcomes by altitude. dd = defense downed/declared dead. fc = fair catch. oob = out of bounds. pr = punt return. tb = touchback.

It appears that there are more touchbacks in Denver, χ² = 92.15, df = 28, p < 0.001. Not much else to say here.

Figure 5. Secondary punt events by altitude. blk = blocked/tipped punt. fum = fumble. muff = returner muffed catch. pen = holding, blocking in back, or clipping penalty on return team. td = touchdown.

There appears to be more penalties in Atlanta and Arizona, but I am unsure why this is. Arizona had six seasons with 5 or fewer wins from 2002-13. ATL had three such seasons. All-around poor team play could have evidenced in more block in the back type penalties on punt returns. 

Figure 6. Punt outcomes as a function of temperature.

I used binary logistic regressions to assess the probability of several punt outcomes associated with several meteorological variables. The meaningful differences (to me) for outcomes due to temperature are between 25° and 75°. Specifically, there is a 5% greater probability of punts being declared dead or downed by the defense (DD) as it gets colder and 5% greater probability of punts being returned when it is warmer. 

Figure 7. Punt outcomes as a function of wind

For wind, I’m looking at the probability difference between no wind and 20mph. The probabilities of fair catches (FCs) decrease and DDs increase as it gets windier. This suggests to me that returners are less likely to even attempt to field the punt when it’s windier. OOBs also increase when it is windier. 

Figure 8. Punt outcomes as a function of precipitation

For precipitation, I’m looking at the change from none to maximum where there is a 5% less probability of a FC when it’s wetter, a 5% greater probability of TBs when it’s wetter, and a 5% greater probability of DD when it’s wetter. Together, these amount to there being fewer punt returns in wetter weather.

In short, the probabilities shown in Figures 6-8 demonstrate to me that punt returners are less inclined to even attempt catching a punt in colder and wetter conditions, and rightfully so. I’m unwilling, however, to conclude exactly the same for windier weather because [a] there are interactions between the meteorological variables not accounted for in these analyses; [b] the analysis accounts for the direction of neither the wind nor the punt; [c] steady winds and, more so, powerful wind gusts could dramatically alter the trajectory of a punt, and leave a return man far out of position. However, as shown above, windier, colder, and wetter conditions reduce punt distance meaning that the coverage unit is approaching the returner much quicker. 

Then I identified 7, 6, and 9 classes, respectively, for temperature, wind, and precipitation using an estimation-maximization procedure. I used these classes to examine the probabilities between meteorological variables and several secondary events: blocks, muffed catches, fumbles, penalties, turnovers, and TDs.  There was no difference in the distribution of PR TDs, fumbles, or turnovers between the classes of any meteorological variable (not shown). 

Figure 9. Muffs as a function of temperature and wind

For muffs, see Figure 9. It appears there is no difference in the distribution across precipitation (χ² = 12.1, p = 0.15; not shown) but the distribution does differ across wind (χ² = 15.9, p = 0.007) and temperature (χ² = 30.92, p < 0.001). Specifically, muffs increased in windier and colder conditions.

Figure 10. Blocked/tipped punts as a function of precipitation and wind

Shown in Figure 10 are blocked punts, which I’m wary of even broaching since it is such a rare event. There is no difference for temperature but there is a difference in the distribution across wind and precipitation. Blocks appear to be slightly less random when it is windier and wetter, but this could be due to adverse conditions affecting punt trajectory or increased pressure due to the expectations that punting is complicated by such weather conditions. However, we must be mindful that there are fewer samples at the meteorological extremes and the results very well could be spurious.

Figure 11. Block in the back, holding, or clipping penalties on the return team as a function of temperature

Distributions of block in the back, holding, or clipping penalties on the return team are no different for wind and precipitation. However, the distributions do differ across temperature such that penalties become more likely in warmer temperatures (χ² = 23.4 , p < 0.001). Penalties likely increase as temperature increases not because of some pressure exerted by warmer conditions per se but, rather, because punt returns are more likely as temperature increases. The odds of a penalty occurring on a punt that is returned are 4.6 times greater than on a punt with no return (z = 26.7, p < 0.001) whereas the odds of a penalty increase by about 0.004 for 1° increase in temperature (z = 3.03, p = 0.002), or by about 0.12 for an increase of 30°.

Summarily, very high altitudes increase punt yards. Colder, wetter, and windier weather reduce punt yards. There is a negligible influence of meteorological variables on punt return yards of returned punts. Punt returners, I subsume, are less likely to attempt to catch a punt during inclement weather. Fumbles, turnovers, and TDs appear to be stochastic and independent of the influence of meteorological conditions. Muffs, however, do appear to increase when it is colder and windier but not in greater precipitation. It seems blocked punts are slightly less random as precipitation and wind increase but these are the rarest of rare events. Penalties are slightly more likely to occur as temperature increases but this is likely due to there being more punt returns in warmer weather. So, that covers meteorology and punting with a healthy dose of chart gluttony.