After 14 years of actively handicapping NFL games versus the Vegas line, I have had the chance to explore literally hundreds of different trends based on a vast array of stats and situational factors, covering almost every facet of the game.

The key word above is 'almost' and one area I have not focused on up until this point concerns game conditions, a category which includes such variables as: game-time temperature, humidity and wind speed along with playing surface type as well as the general weather conditions (aside from temperature and humidity) present at the start of the game (i.e., Partly Sunny, Cloudy, Snow, Light Rain, etc).

The biggest reason I have ignored this data over the past decade-and-a-half is probably more an issue of timing than anything else: Making wagers based on weather conditions is a difficult task 6 days before a game is actually due to be played--which is roughly when my full analysis is normally released to my customers and anyone else that may be interested in some of the sample trends I provide.

Ultimately, the determination of whether or not a weather-based trend is or isn't in play has to be made in the 30-60 minutes before game-time, which obviously doesn't fit into my existing schedule all that well.

Despite this, I thought it still might be worthwhile to look at some of these factors over the summer of '08 and using game book data from the past 7 seasons, I have now added the following 6 columns to my database to allow for further study:

Temperature (TEMP)
Humidity (HUMD)
Wind Speed (WSPD)
Wind Direction (WDIR)
General Conditions (COND)
Playing Surface (SURF)

The first 5 of these are all based on the weather measurements taken at game-time and my data is not, unfortunately, advanced enough to account for whether the sun came out five minutes into a game that started out under a heavy-rainfall, or where the wind increased by 10 mph in the second half, etc, etc.

Also, while I tried my best to standardize and simplify the general 'conditions' listed in each game book (i.e., Chance of Rain, Partly Sunny, etc.), one on-site documenters interpretation of 'Light Snow' could look more like a 'Snow Storm' to someone else, depending on whether they happen to be from Florida, or Fargo.

Add the end of the day, this underlying subjectivity should be taken into account when attempting to use this information as a 'hard-and-fast' tool for handicapping purposes.

The various limitations of this data not with-standing, I have managed to locate a few interesting trends that have been present in the past 7 years and I will be showcasing some of these over the next few months in the form of 'Simple Systems' articles, exactly like this one.

One of the first things that jumped out at me after crunching the numbers for a few days is that: Favourites of at least 3 points are an excellent wager at a specific temperature range.

What is this temperature range you ask? It happens to be between 20 degrees Fahrenheit and 34 degrees Fahrenheit, the latter of which is just a hair above the freezing point of 32 degrees.

Favourites of at least 3 points that are playing within this temp range are an excellent 44-26 (62.9%) ATS since 2001, producing a profit of $1,540.00 at 10/11 odds ($110 wagered to win back $100 on each game). This situation has actually been equally powerful for both home favs and road ones. It is 37-23 ATS at home and a comparable 7-3 ATS on the road.

Before I go any further, there are some potential 'red-flags' that this situation raises which does put into question how well it may perform in 2008 and beyond. The first is the fact that less than half the teams in the league have fallen into this situation (46.9% to be exact) since 2001--obviously, because many teams simply don't play in these colder outdoor conditions that often. In addition, we also happen to be dealing with a fairly narrow range as far as the game-time temperature goes that may or may not be truly significant over the long-run.

While I am cautionary about this trends future potential, it is certainly significant enough to warrant closer study in the coming season and I am even more confident of this fact after 2 Secondary conditions are added into the mix.

The first of these is to remove any games before Week 13 and in the Playoffs. This situation has had mixed results prior to Week 13 and in the Post Season, where a different set of rules apply as far as how teams typically behave versus the spread.

By including only games between Week 13 and 17, we are essentially only looking at contests within the month of December, where a temp range of 20 to 34 degrees is most prevalent anyway. Once this condition is added, the record improves greatly to 34-12 (73.9%) ATS.

The 2nd and final secondary condition for this situation is weather-related and it specifies that the game-time humidity is at least 50%.

Anyone familiar with the term 'humidex' is aware of the uncomfortable effect that higher humidity levels can have when combined with high temperatures.

What is not as well known is that fact that higher humidity levels can also increase the level of discomfort in cold conditions due to the effect of increased moisture levels in the air that can permeate into clothing, serving to make the air feel colder than it actually is.

Once again, in this case, the favourite seems to benefit and after eliminating all games with a below-average humidity level, this situation improves to 34-8 ATS (81.0%) with a profit of $2,520.00 over the past 7 years.

For those interested in using this situation in 2008: Here is a complete summary of all it's details.

(Notes: ASMR stands for Average Spread Margin Rating. A positive rating indicates a trend that is stronger than average versus the line, negative--weaker than average. TDIS% is the percentage of teams in the league that have been involved in this situation at one time or another. WT% is the percentage of teams that are .500 or better and SPR is the average spread for teams in this situation. For more details, please consult Page 13 of my 2007 NFL Game Sheets Guide.)

System #112 Summary

Primary Conditions (Building Blocks)
1) Favourite of > 3 PTS.
2) Game Time Temperature of 20-34 degrees Fahrenheit.

Secondary Conditions (Tighteners)
1) Week 13 to 17.
2) Game Time Humidity >= 50%.

System Stats
ASMR: 1.6
Home%: 76.2
Dog%: 0.0
TDIS%: 43.8
WT%: 85.7
SPR: -6.8
Top Teams: PIT(8); GB(7); NE(7); DEN(4)

System Record
Overall (Since '01): 34-8 ATS
2007 Season: 7-0 ATS
2006 Season: 2-1 ATS
2005 Season: 9-1 ATS
2004 Season: 6-2 ATS

Last 3 Results. Pick in Brackets
2007 WK17--GB 24 DET 13 (GB -4) W
2007 WK15--TEN 26 KC 17 (TEN -3.5) W
2007 WK15--CLE 8 BUF 0 (CLE -6) W