Issue #21141 has been updated by nobu (Nobuyoshi Nakada). Maybe also this is related: ```ruby ENV["TZ"] = "UTC" p Time.now.utc? #=> false ``` Is it expected? In other words, is that `Time#utc?` is true a special case, only when the time is created with the methods such as `Time.utc`, `Time#utc`, etc, that clearly return a UTC time object? ---------------------------------------- Bug #21141: `Time#utc?` does not work with a timezone object https://bugs.ruby-lang.org/issues/21141#change-111983 * Author: nobu (Nobuyoshi Nakada) * Status: Open * Backport: 3.1: REQUIRED, 3.2: REQUIRED, 3.3: REQUIRED, 3.4: REQUIRED ---------------------------------------- ```ruby require 'timezone' require 'tzinfo' t = Time.now(in: "UTC") t_timezone = Time.now(in: Timezone["UTC"]) t_tzinfo = Time.now(in: TZInfo::Timezone.get("UTC")) p t.utc? #=> true p t_timezone.utc? #=> false p t_tzinfo.utc? #=> false ``` This also affects `strftime("%-z")`. -- https://bugs.ruby-lang.org/