Peru's 'Day Without Shadows' Arrives: What Causes This Rare Solar Phenomenon and When Lima Will See It in 2026

Pedestrians walk under direct sunlight in Peru during the astronomical phenomenon known as "shadowless days" (solar zenith passage), when the Sun positions itself directly overhead at a 90-degree angle, temporarily causing vertical objects and people to cast almost no side shadow at midday. (Credit: Photo: Andina Agency / Diffusion)

The Briefing

• When and where: Lima and Callao are currently in the middle of their "Days Without Shadows" window—a multi-day event running from October 22 to October 25, 2026, with the peak effect occurring between 11:50 and 11:52 a.m. each day.
• What happens: As the sun positions itself almost directly overhead, the lateral shadows cast by people, buildings, and any upright object shrink to nearly nothing for a few minutes around noon.
• Health alert: Senamhi has issued UV protection guidance for Lima and Callao tied to this event; avoid unprotected midday sun exposure between 9 a.m. and 4 p.m. and apply sunscreen before stepping outside.