Monarch butterflies pass through on fall migration

September 22, 2026

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butterflies were recorded at nine locations from August 24 through September 13, 2026, with the most recent sighting on September 13 in Salt Lake City.¹ The peak fall migration window for Utah monarchs runs September 1-30, meaning these observations capture the early phase of the annual southbound movement toward Mexican overwintering grounds.¹ Western monarch populations have declined drastically, with current numbers below historical levels, making each migration cycle critical for species persistence.¹

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