Weather meaningfully moves MLB scoring. Cold under 60F suppresses runs by 0.3-0.5 per game. Warm 80F+ with wind out adds 0.4-0.7 runs. Wind direction matters most at hitter parks (Wrigley, Yankee Stadium). Sharp models include weather as a 5-10% variance contributor on totals.
Weather is one of the most underweighted MLB betting factors at the public level. Cold suppresses scoring; warm boosts it. Wind blowing out helps HRs; wind blowing in kills them. Humidity has minor effects. Sharp models include weather as a meaningful input on totals (5-10% of total variance) and a smaller input on moneylines (1-3%).
Wind direction matters MOST at parks where the wind interacts with the outfield orientation. Wrigley Field is notorious because the lake breeze either blows out (HRs everywhere) or blows in (warning-track outs).
Most affected parks:
Less affected parks (domed, sheltered, or naturally calm):
High humidity reduces ball flight slightly (denser air slows it). Low humidity (dry) helps the ball travel. The effect is small (0.10-0.15 runs) and usually only noticed at high-altitude or extreme-condition parks.
Coors Field uses a humidor to control ball density; humidity has minimal effect there. Other parks the weather drives natural humidity changes.
Cold weather often correlates with larger called strike zones (umpires want games to end faster, batters chase more in cold). Hot weather correlates with tighter zones. Net effect: cold weather has compounding under effect (suppressed scoring + larger zone), hot weather has compounding over effect (boosted scoring + smaller zone).
Best weather over plays:
Best weather under plays:
Check the forecast at game-time start, not at noon. Weather can change in 6 hours.
The model pulls hourly weather forecasts for each game's start time. Inputs include temperature, wind speed, wind direction, humidity, and pressure. Each is converted to a run-expectancy adjustment based on the specific ballpark's exposure (Wrigley wind effects differ from Marlins Park). The brain has learned weather inputs as a 5-10% variance contributor on totals. See the methodology page for the full weather adjustment logic.
Yes, meaningfully. Cold under 60F suppresses scoring by 0.3-0.5 runs per game. Warm 80F+ with wind out adds 0.4-0.7 runs. Wind direction matters most at hitter parks (Wrigley Field famously). Sharp models include weather as a 5-10% variance contributor on totals and 1-3% on moneylines.
Wind blowing out 10+ mph adds 0.4-0.7 runs to expected totals (HR rate up 20-40%). Wind blowing in 10+ mph subtracts 0.4-0.7 runs. Effect is largest at hitter parks with exposed outfields (Wrigley, Yankee Stadium, Citizens Bank Park). Domed and sheltered parks (Marlins Park, Tropicana, Globe Life) have no wind effect.
Best MLB weather strategy: bet OVER when 80F+ at hitter park with wind out 10+ mph (especially Wrigley, Coors, Citizens Bank in July). Bet UNDER when under 55F at non-domed park with wind in 10+ mph (April/May Wrigley with wind in, Oracle Park with wind from McCovey Cove). Check forecast at game time, not noon.
Most weather-affected parks: Wrigley Field (CHC - lake wind dominates), Yankee Stadium (short right-field porch), Citizens Bank Park (PHI - jet stream summer), Oracle Park (SF - McCovey Cove wind), Coors Field (COL - altitude + wind). Least affected: domed parks (Tropicana, Marlins Park) and retractable-roof parks usually closed (Globe Life).
Yes. Cold under 50F suppresses scoring 0.5-0.8 runs (ball doesn't travel, bat speed drops, breaking balls play better). 50-60F: 0.3-0.5 runs suppression. 60-75F: neutral baseline. 75-85F: 0.2-0.4 runs boost. 85F+ humid: 0.5-0.7 runs boost. Temperature effect compounds with wind direction for total weather adjustment.