Timing window is the elapsed "real time", usually short, in which certain important strategical advantage is active before it gets countered by the opponent. In other words it is a small window of opportunity where your opponents strategy is vulnerable to your own strategy. To exploit this timing window you must attack your opponent with the appropriate counter.
Most of the time it refers to the time in which certain upgrade will be researched for a player and not for the other in mirror matches, but it can apply to non-mirror matches and to a purely production advantage too.
- In PvP games when a player gets +1 attack upgrade faster than the other. The timing window until the opponent gets the +1 attack upgrade gives this player a big army advantage.
- In PvP where a player has Dragoon Range done while the other player does not
- In PvZ when Protoss gets +1 ground attack upgrade there is a timing window where |Zealots are considerably stronger against Zerglings until Zerg gets +1 defense upgrade.
- In TvZ where 2 Hatch Muta abuses the fact that Terran has Mutalisks in his base before U-238 shells (range) is finished.