Surge follows demand spikes you can see coming: weekday rush hours, sudden rain, the end of matches and concerts, holidays, and the dead zone after public transit stops. During those windows app fares commonly rise to a noticeable multiple of the normal price, occasionally dramatically during extreme moments like New Year's Eve. Regulated metered taxis in many cities do not surge, though some add official night, holiday, or rain surcharges, so during heavy surge a traditional taxi can quietly become the cheaper option, a reversal that surprises people.
Alternatives worth having in your pocket: walking a short distance away from the epicenter, since surge zones are small and prices drop a few blocks out; waiting twenty or thirty minutes, because spikes usually decay quickly; comparing a second ride app, as they surge independently; and public transit, which often runs extra service during big events precisely to absorb the crowd.
For unavoidable peak trips like a rush-hour flight, some apps let you schedule a ride in advance or lock a fare, and a hotel-booked car at a fixed price removes the gamble entirely. Planning around the spike beats paying it.