ATP Tour Analysis / 2018–2024

Do players perform worse
between cold and hot conditions?

Continuous correlation analysis of wet-bulb temperature deltas and match performance across 7,500+ first-round tournament appearances by top-100 ATP players.

At a Glance

Main Result

Performance by Wet-Bulb Temperature Delta ?Wet-bulb temperature accounts for both heat and humidity. The delta is the difference between the player's current tournament and their previous one. Positive = moving to hotter/more humid conditions.

Correlation Details

Metric	Pearson r ?Pearson correlation coefficient. Ranges from -1 to +1. Measures the linear relationship between wet-bulb delta and this metric. Negative = metric decreases as delta increases.	P-Value ?Probability of seeing this correlation by chance. Below 0.05 is conventionally considered statistically significant. Below 0.01 is highly significant.	Slope ?Linear regression slope: how much the metric changes per 1°C increase in wet-bulb delta. For percentage metrics, shown in percentage points (pp).	N	Sig. ?Statistical significance level. Green dot = p<0.05 (significant). Yellow dot = p<0.10 (marginal). Grey dot = not significant.

Methodology

Data

Match data from Jeff Sackmann's open-source ATP database. Wet-bulb temperatures from Open-Meteo's historical archive API (7-day tournament mean). Rankings from official ATP ranking files.

Sample

Every top-100 player's first match at each tournament where both the current and previous tournament have weather data. This isolates the acclimatization moment.

Dominance Ratio

The established single-number match performance measure: DR = return pts won % / service pts lost %. DR > 1.0 means the player dominated; DR < 1.0 means they were dominated.

Elo Model

Match-by-match Elo ratings (K=32) built from all ATP results. Over/under-performance = actual result - expected win probability. Controls for opponent strength.

Current Top 100 — Performance in Temperature Transitions

#	Player	Matches ?Number of first-match-at-tournament records where weather data was available for both the current and previous tournament.	Win % ?Win rate across all transition matches (first match at each tournament). Not overall career win rate.	Avg Delta ?Average wet-bulb temperature delta across all transition matches. Positive = on average moved to hotter conditions.	Avg DR ?Average Dominance Ratio across transition matches. Above 1.0 (green) = dominated opponents on average. Below 1.0 (red) = was dominated.	Elo +/- ?Average Elo over/under-performance. Positive (green) = beat expectations. Negative (red) = underperformed. Controls for opponent strength.