18 May 2026

• 138th day of the year. There are then 227 days left in 2026.
• 20th Monday of 2026.
• on the 20th week of 2026 (using ISO standard week number calculation).
• Birthstone for this day: Emerald

There are no major holidays or observances in South Africa for this date.

• International Museum Day - Popular in: United States, India, United Kingdom, Canada
• Haitian Flag Day - United States
• Día de la Escarapela (Argentina) - Argentina
• Ascensión del Señor - Traslada - Colombia
• Dia Nacional do Combate ao Abuso e Exploração Sexual de Menores - Brazil
• National Law Week Begins - Australia
• Día Internacional de los Museos - Popular in: Spain
• National Patriots' Day (QC) - Canada