Key Takeaways: Weather Effects

One-Page Reference

Weather Impact Summary

Quick Calculation

Temperature:

If Temp < 55°F:
   Adjustment = -0.12 × (55 - Temp)
   Example: 30°F → -0.12 × 25 = -3.0 pts

Wind:

If Wind > 10 mph:
   Adjustment = -0.25 × (Wind - 10)
   Example: 22 mph → -0.25 × 12 = -3.0 pts

Venue Types

Indoor (no weather): - Cowboys, Saints, Falcons, Vikings - Raiders, Rams/Chargers, Cardinals, Lions

Cold Weather Outdoor: - Packers, Bears, Bills, Patriots - Steelers, Browns, Bengals, Eagles - Giants/Jets, Ravens, Commanders

Spread Adjustments (Asymmetric)

Cold Game (< 30°F):
- Dome team visiting cold weather: +1.0 to +2.0 pts
- Cold team hosting dome team: -0.5 to -1.5 pts

High Wind (> 20 mph):
- Pass-heavy team: +1.0 pts (disadvantage)
- Run-heavy team: -1.0 pts (relative advantage)

Altitude (Denver Only)

Empower Field at Mile High:
- Total: +1.5 points (easier scoring)
- Field Goals: +2-3 yards range
- Home advantage: +0.5 to +1.0 additional
- Visiting sea-level teams: -0.5 to -1.0 pts

Weather Index Formula

Index = Temp_Factor + Wind_Factor + Precip_Factor

Temp_Factor = max(0, 55 - Temp) × 0.10
Wind_Factor = max(0, Wind - 10) × 0.15
Precip_Factor = (0 none, 1.5 light rain, 3.5 heavy rain, 5.0 snow)

Index Interpretation:
0-1: Ideal conditions
1-3: Minor impact (-1 to -2 pts)
3-5: Moderate impact (-3 to -5 pts)
5-8: Significant impact (-5 to -8 pts)
> 8: Extreme conditions (-8+ pts)

Market Efficiency

Usually Well-Priced: - Extreme cold (obvious to all) - High-profile snow games - Forecasted precipitation

Potential Opportunities: - Wind effects (underweighted) - Last-minute forecast changes - Heat/humidity (early season)

Data Sources

Integration Workflow

1. Check venue type
   - Indoor → No adjustment
   - Retractable → Check forecast

2. Get forecast for game time
   - Temperature
   - Wind speed/direction
   - Precipitation

3. Calculate adjustments
   - Total adjustment (always)
   - Spread adjustment (if asymmetric)

4. Apply to base prediction
   - Weather-adjusted total
   - Weather-adjusted spread

Key Insight

Wind is the most impactful weather factor because it directly affects ball flight and is hardest to prepare for. Cold affects both teams similarly (impacting totals more than spreads), while precipitation creates high variance. Markets generally price obvious weather conditions but may underweight wind.