NFL Weather Factors
When handicapping the NFL, it’s important for bettors to consider all the factors involved in the game, not just the strength of each team, the coaches’ game plans, and team motivations. One aspect that many recreational bettors don’t give a second thought to is the weather.
The sportsbooks aren’t oblivious to weather factors. In fact, it’s much to the contrary. Weather factors are massively influential in terms of line movement.
Understanding how different types of weather may affect a game is crucial to evaluating NFL contests and the oddsmakers’ ability to account for these effects in the odds.
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Do The Sportsbooks Accurately Account For Weather?
To examine this question, we have to look at the different types of weather and the environments of NFL games. It’s important to note that several teams in the NFL plan in dome stadiums and a few more play in stadiums that have retractable roofs.
Home games for the Atlanta Falcons, New Orleans Saints, St. Louis Rams and Minnesota Vikings are all played, in domes, and, therefore, have a static, but favorable weather environment. The Houston Texans, Arizona Cardinals, and Indianapolis Colts all play in stadiums with retractable roofs. When playing at home, these teams essentially become dome teams in the event if extreme or inclement weather.
It shouldn’t be a shock that the oddsmakers do an excellent job handicapping contests in domes and outdoor games with almost no severe weather factors. They’re acutely aware that domes produce more points than outdoor games in general and adjust appropriately based on other conditions.
From 2003 to 2013, the average points per game scored in dome contests was around 46 points about four full points higher than games played outdoors, which came in at about 42 points per contest. Teams score more points in the closed environments of domes rather than outdoors on the whole, especially with the high percentage of cold weather games that in the months of late November and December.
Of course, when talking about outdoor games, we’re looking at a broad range of weather conditions.
Warm vs. Cold
Games in warmer weather produce more points than those in colder weather. It’s easy to see the drop in completion percentage and field goal percentage as the season progresses and outdoor games get colder.
The reasons should be obvious. Players are used to playing in practice environments with stable temperature conditions, which allows them to minimize distractions when it’s a bright sunny day.
Quarterbacks will have more flight on their balls and kickers will get more air under their attempts with the warm air, and catching balls in cold temperatures is much tougher than when it’s warm.
Extreme heat can be an issue for teams playing outdoors, but most teams that play in areas where there may be excessive heat usually have a dome or retractable roof. It might not be much of a factor either, except in the case of general fatigue. Quarterbacks see little drop off in their production in yards per attempt, even as temperate rise over 80 degrees.
For the most part, the oddsmakers’ opening numbers accurately account for contests in domes and the general climate, aside from extreme weather conditions.
It’s not as if oddsmakers don’t account for extreme weather, however. It’s just tough for these factors to be incorporated into the opening odds, simply because the game is a week in advance and weather seven days from now is relatively unknown or unreliable.
Adjustments for extreme weather, which will almost certainly negatively impact scoring at least slightly can’t be made until later in the week. Bettors may see a total open up and drop drastically later in the week when the forecast calls for a snowstorm. As we get closer to game day, this data becomes more accurate, and the sportsbooks adjust to weather reports.
How much rain, sleet, snow, and hail affect a game is up for debate among many. The one extreme weather condition that bettors need to pay extra attention to is the effect of wind speeds.
For most contests, the wind isn’t much of a factor. Most games have low-level wind speeds that don’t affect the outcome of the game. However, once winds start to gust over 14 miles per hour, there’s a significant drop-off in scoring. Once wind speeds get over 30 mph, the effect is especially potent.
In games where wind speeds range from 1-14 mph hour, teams average somewhere between 40-43 points per game. As speeds increase to 15-20 mph, this number drops to around 40 points per game.
As wind speeds get faster than 20 mph, the effects are even starker. These games will average around just 35 points per game. 30-40 mph and over gusts is just about as extreme as you can get regarding weather affecting the outcome.
Teams will cut down passing attempts and run the ball considerably more due to the wind’s effect on the passing game. The yards per attempt on each throw drop dramatically as wind speeds pick up. The kicking game also predictably suffers.
Wind Data in the Past
Data from PinnacleSports.com, from the 2003-2013 seasons show that the oddsmakers may not appropriately be accounting for the adverse effects of wind speed. When it comes to games affected by high winds, bettors seem to have a distinct advantage when betting the under:
“And the best-predicted fit from the data for the strike rate of games going under the quoted total when the average wind speed is 15 mph is 54.5%. The percentage of unders then remains consistently above this figure as winds strengthen even more. For example, at average speeds of 17 mph, the likelihood of the match total going under the quote rises to 55.6% and hits 60% at 25 mph.
In the 50 or so such games, average totals were set on the low side at 38.5, but actual match totals averaged even lower at 35.3 and consequently under bets were successful in 64.6% of games.”
Weather Factors Strategy
As discussed above, weather factors are relatively unrepresented in the opening line and early part of the NFL line cycle.
It’s tough to draw many conclusions from that far away from game day, but it does offer a baseline to the general conditions that might be factored into the line. Bettors have an opportunity to wager earlier in the week if the conditions look unfavorable, such as the potential for high winds or snow.
Betting the Under
Betting the under as the odds open can be a sound strategy that offers players the chance to grab an elite price if the market changes due to inclement weather. Even if the weather forecast results in non-extreme weather, bettors have taken an under at a neutral price while the market was at its least efficient stage.
Alternatively, waiting till news breaks on inclement weather and then betting the lines before a market move is another option.
Get Constant Updates to Beat the Betting Sites
Conventional wisdom would suggest that sportsbooks would receive this information faster than gamblers, but as we discussed in our Tipoff Time NBA article, bettors can sometimes beat them to the punch.
Constantly looking at weather reports is a tedious process and undoubtedly not something that everyone has the time to do. Luckily, in today’s information age there are plenty of ways to get important sports news quickly. Twitter is the best way to get news faster than anywhere else.
Other NFL Weather Strategies to Consider
There are other factors to consider as well. Depending on the coaching staff, the gameplan for a poor weather game may be altered dramatically on offense. Defensively, things won’t likely change much, but if you’ve got a suspicion that an offensive coordinator will change much of his gameplan due to extreme weather, there may be an opportunity.
Changing Up the Offense – If the gameplan turns towards a more run-heavy affair, the skill of the offensive and defensive lines when it comes to run blocking and run stopping becomes all the more important. Likewise, the talent of each team’s running backs.
This can draw you to bet the underdog or the favorite, depending on which side the change in conditions benefits most.
Severe Weather – In the same vein, severe weather affects teams in an overall sense much differently. We all know the trouble that teams from warmer cities or environments have playing in colder conditions, particularly in the final month of the season where temperatures considerably. If near freezing playing conditions and/or snow are on the horizon, it may be worth firing off a bet the team that is more experienced playing in that kind of weather.