The same bowler can look transformed by a change of continent, and part of the reason sits in his hand. Cricket balls are made differently in different places.
The seam is the aerodynamic feature
A cricket ball swings because the raised seam disturbs airflow on one side while the other side stays smooth.
How proud that seam stands, and how long it stays proud, depends on how the leather halves are stitched together and how tightly the rows are packed.
A ball with a pronounced, durable seam keeps interfering with the air for many more overs than one whose seam flattens quickly.
Leather and lacquer control the surface
The shine on a new ball is partly lacquer applied at manufacture. While it lasts, one polished side stays smooth and swing is available.
Heavier lacquering keeps a ball glossy longer but can delay the roughening that produces reverse swing later in an innings.
Leather tanning also varies. Softer leather scuffs sooner on abrasive surfaces, hardens differently in dry heat, and takes moisture in a different way.
Conditions and construction reinforce each other
Overhead conditions matter, but so does what the outfield does to the ball. A dry, coarse outfield abrades one side quickly and shortens the conventional swing phase.
Lush, damp outfields preserve the shine, which is one reason bowlers in cooler climates keep the ball moving through the air for longer.
The combination explains why a ball type that dominates in one country can feel inert in another even in similar weather.
What this does to bowling plans
Where the seam stays hard, seam movement off the pitch remains available deep into an innings and captains keep quicker bowlers in longer spells.
Where the ball softens, the middle overs become a holding phase, spin arrives earlier, and the plan resets when the second new ball is due.
Why touring bowlers take time to adjust
Wrist position, seam presentation and the length that draws a false shot are all calibrated to a specific ball's behaviour.
A bowler arriving in a new country is recalibrating that feel while playing competitive cricket, which is why performances often improve across a series rather than at the start of one.
It is also why domestic records travel unevenly, and why selectors weigh where a bowler's wickets were taken as heavily as how many.