The trade range was recently increased again in Pokémon GO. Read on below to learn more:
Limited-time test: Trade range increased until Monday, November 30, 2020, at 1 p.m. PST (GMT −8)
Trainers,
As a limited-time test, from Wednesday, November 18, 2020, until Monday, November 30, 2020, at 1:00 p.m. PST (GMT −8), trade range will be increased! Depending on information gathered from this test, we may include increased trade range as a part of future events.
It’s time to trade, Trainers!
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—The Pokémon GO team
Source: Official Pokémon GO blog