of National Library week, April 4) National Bookmobile Day (Wednesday of National Library week, April 5) National Public Health Week (United States) National Public Safety Telecommunicators Week (United States) Second Wednesday: April 8 International Day of Pink Second Thursday: April 9 National Former Prisoner of War Recognition Day (United States) Second Friday of April: April 10 Fast and Prayer Day (Liberia) Air Force Day (Russia) Kamakura Matsuri at Tsurugaoka Hachiman (Kamakura, Japan), lasts until third Sunday. Second Sunday: April 12 Children's Day (Peru) Week of April 14: April 12–18 Pan-American Week (United States) Third Wednesday: April 15 Administrative Professionals' Day (New Zealand) Third Thursday: April 16 National High Five Day (United States) Third Saturday: April 18 Record Store Day (International observance) Last full week of April: April 19–25 Administrative Professionals Week (Malaysia, North America) World Immunization Week Week of April 23: April 19–25 Canada Book Week (Canada) Week of the New Moon: April 19–25 National Dark-Sky Week (United States) Third Monday: April 20 Patriots' Day (Massachusetts, Maine, United States) Queen's Official Birthday (Saint Helena, Ascension and Tristan da Cunha) Sechseläuten (Zürich, Switzerland) Wednesday of last full week of April: April 22 Administrative Professionals' Day (Hong Kong, North America) First Thursday after April 18: April 23 First Day of Summer (Iceland) Fourth Thursday: April 23 Take Our Daughters And Sons To Work Day (United States) Last Friday: April 24 Arbor Day (United States) Día de la Chupina (Rosario, Argentina) Last Friday in April to first Sunday in May: April 24-May 3 Arbour Week in Ontario Last Saturday: April 25 Children's Day (Colombia) National Rebuilding Day (United States) National Sense of Smell Day (United States) World Tai Chi and Qigong Day Last Sunday: April 26 Flag Day (Åland, Finland) Turkmen Racing Horse Festival (Turkmenistan) April 27 (moves to April 26 if April 27 is on a Sunday): April 27 Koningsdag (Netherlands) Last Monday: April 27 Confederate Memorial Day (Alabama, Georgia (U.S. state), and Mississippi, United States) Last Wednesday: April 29 International Noise Awareness Day Fixed observances April 1 April Fools' Day Arbor Day (Tanzania) Civil Service Day (Thailand) Cyprus National Day (Cyprus) Edible Book Day Fossil Fools Day Kha b-Nisan (Assyrian people) National Civil Service Day (Thailand) Odisha Day (Odisha, India) Start of Testicular Cancer Awareness week (United States), April 1–7 Season for Nonviolence January 30 – April 4 April 2 International Children's Book Day (International observance) Malvinas Day (Argentina) National Peanut