| Thu, April 1 | National Poetry Month | - | Monthly |
| Thu, April 1 | National One Cent Day | - | Weird |
| Thu, April 1 | National Sourdough Bread Day | - | Weird |
| Thu, April 1 | April Fools Day | - | Weird |
| Thu, April 1 | National Burrito Day | - | Weird |
| Fri, April 2 | International Children's Book Day | - | Weird |
| Fri, April 2 | National Reconciliation Day | - | Weird |
| Fri, April 2 | National Peanut Butter and Jelly Day | - | Weird |
| Fri, April 2 | National Ferret Day | - | Weird |
| Sat, April 3 | National Film Score Day | - | Weird |
| Sat, April 3 | National Tweed Day | - | Weird |
| Sat, April 3 | National Chocolate Mousse Day | - | Weird |
| Sat, April 3 | National Find a Rainbow Day | - | Weird |
| Sat, April 3 | National Love Our Children Day | - | Weird |
| Sun, April 4 | National Vitamin C Day * | - | Weird |
| Sun, April 4 | National Walk Around Things Day | - | Weird |
| Sun, April 4 | National Hug a Newsperson Day | - | Weird |
| Sun, April 4 | National School Librarian Day | - | Weird |
| Sun, April 4 | National Chicken Cordon Bleu Day | - | Weird |
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| Sun, April 4 | Jeep 4×4 Day | - | Weird |
| Mon, April 5 | First Contact Day | - | Weird |
| Mon, April 5 | National Flash Drive Day | - | Weird |
| Mon, April 5 | National Go For Broke Day | - | Weird |
| Mon, April 5 | National Caramel Day | - | Weird |
| Mon, April 5 | National Read a Road Map Day | - | Weird |
| Mon, April 5 | National Raisin and Spice Bar Day | - | Weird |
| Mon, April 5 | National Deep Dish Pizza Day | - | Weird |
| Mon, April 5 | National Nebraska Day | - | Weird |
| Tue, April 6 | National Tartan Day | Multiple [Show] | Observance |
| Tue, April 6 | National Sorry Charlie Day | - | Weird |
| Tue, April 6 | New Beer’s Eve | - | Weird |
| Tue, April 6 | National Caramel Popcorn Day | - | Weird |
| Tue, April 6 | National Student-Athlete Day | - | Weird |
| Tue, April 6 | National Teflon Day | - | Weird |
| Tue, April 6 | SAAM Day of Action | - | Weird |
| Tue, April 6 | National Library Workers Day | - | Weird |
| Wed, April 7 | United Nations' World Health Day | - | International |
| Wed, April 7 | National Beer Day | United states | |
| Wed, April 7 | National Coffee Cake Day | - | Weird |
| Wed, April 7 | National No Housework Day | - | Weird |
| Wed, April 7 | National Girl Me Too Day | - | Weird |
| Wed, April 7 | National Handmade Day | - | Weird |
| Wed, April 7 | National Bookmobile Day | - | Weird |
| Wed, April 7 | National Walking Day | - | Weird |
| Wed, April 7 | Childhelp National Day of Hope | - | Weird |
| Thu, April 8 | National All is Ours Day | - | Weird |
| Thu, April 8 | National Zoo Lovers Day | - | Weird |
| Thu, April 8 | National Empanada Day | - | Weird |
| Thu, April 8 | National Alcohol Screening Day | - | Weird |
| Fri, April 9 | National Cherish an Antique Day | - | Weird |
| Fri, April 9 | National Name Yourself Day | - | Weird |
| Fri, April 9 | National Winston Churchill Day | - | Weird |
| Fri, April 9 | National Chinese Almond Cookie Day | - | Weird |
| Fri, April 9 | National Former Prisoner of War Recognition Day | - | Weird |
| Sat, April 10 | Siblings Day | - | |
| Sat, April 10 | National Farm Animals Day | - | Weird |
| Sun, April 11 | National Pet Day | - | Weird |
| Sun, April 11 | National Barber Shop Quartet Day | - | Weird |
| Sun, April 11 | National Submarine Day | - | Weird |
| Sun, April 11 | National Teach Children to Save Day | - | Weird |
| Sun, April 11 | National Eight Track Tape Day | - | Weird |
| Sun, April 11 | National Cheese Fondue Day | - | Weird |
| Mon, April 12 | Grilled Cheese Day | - | Weird |
| Mon, April 12 | Yuri's Night | - | Weird |
| Mon, April 12 | National Big Wind Day | - | Weird |
| Mon, April 12 | National Licorice Day | - | Weird |
| Mon, April 12 | National Grilled Cheese Sandwich Day | - | Weird |
| Mon, April 12 | National Colorado Day | - | Weird |
| Tue, April 13 | Songkran | Thailand | National Holiday |
| Tue, April 13 | National Scrabble Day | - | Weird |
| Tue, April 13 | National Thomas Jefferson Day | - | Weird |
| Tue, April 13 | National Peach Cobbler Day | - | Weird |
| Tue, April 13 | National Make Lunch Count Day | - | Weird |
| Tue, April 13 | Ougadi | Mauritius | Public Holiday |
| Tue, April 13 | Telugu New Year/ Ugadi/ Gudi Padwa | - | Hindu |
| Wed, April 14 | Ambedkar Jayanti | India | Observance |
| Wed, April 14 | Cake and Cunnilingus Day | - | Weird |
| Wed, April 14 | National Gardening Day | - | Weird |
| Wed, April 14 | National Reach as High as You Can Day | - | Weird |
| Wed, April 14 | National Pan American Day | - | Weird |
| Wed, April 14 | National Ex Spouse Day | - | Weird |
| Wed, April 14 | National Dolphin Day | - | Weird |
| Wed, April 14 | National Pecan Day | - | Weird |
| Wed, April 14 | Vaisakhi / Baisakhi / Vishu | - | Hindu |
| Wed, April 14 | Tamil New Year | - | Hindu |
| Wed, April 14 | Vaisakhi | India | Restricted Holiday |
| Wed, April 14 | Bengali New Year | Bangladesh | Public Holiday |
| Thu, April 15 | National Take a Wild Guess Day | - | Weird |
| Thu, April 15 | National Rubber Eraser Day | - | Weird |
| Thu, April 15 | National Titanic Remembrance Day | - | Weird |
| Thu, April 15 | National Glazed Spiral Ham Day | - | Weird |
| Thu, April 15 | Get to Know Your Customers Day | - | Weird |
| Thu, April 15 | Tax Day | United states | Observance |
| Fri, April 16 | Wear Pajamas to Work Day | - | Weird |
| Fri, April 16 | National Orchid Day | - | Weird |
| Fri, April 16 | National Eggs Benedict Day | - | Weird |
| Fri, April 16 | National Wear Your Pajamas to Work Day | - | Weird |
| Fri, April 16 | National Healthcare Decisions Day | - | Weird |
| Fri, April 16 | National Bean Counter Day | - | Weird |
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| Sat, April 17 | Herbalist Day | - | Weird |
| Sat, April 17 | National Bat Appreciation Day | - | Weird |
| Sat, April 17 | National Ellis Island Family History Day | - | Weird |
| Sat, April 17 | National Haiku Poetry Day | - | Weird |
| Sat, April 17 | National Cheeseball Day | - | Weird |
| Sat, April 17 | National Auctioneers Day | - | Weird |
| Sat, April 17 | National Record Store Day | - | Weird |
| Sun, April 18 | Birthday of Guru Angad Dev | - | Sikh |
| Sun, April 18 | National Lineman Appreciation Day | - | Weird |
| Sun, April 18 | National Columnists’ Day | - | Weird |
| Sun, April 18 | National Animal Crackers Day | - | Weird |
| Sun, April 18 | National High Five Day | - | Weird |
| Mon, April 19 | Bicycle Day | - | Weird |
| Mon, April 19 | National Hanging Out Day | - | Weird |
| Mon, April 19 | National Oklahoma City Bombing Commemoration Day | - | Weird |
| Mon, April 19 | National Garlic Day | - | Weird |
| Mon, April 19 | National Amaretto Day | - | Weird |
| Mon, April 19 | National North Dakota Day | - | Weird |
| Mon, April 19 | Sechseläuten | Switzerland (Zurich) | Observance |
| Tue, April 20 | Lima Bean Respect Day | - | Weird |
| Tue, April 20 | National Cheddar Fries Day | - | Weird |
| Tue, April 20 | National Look Alike Day | - | Weird |
| Tue, April 20 | National Pineapple Upside Down Cake Day | - | Weird |
| Wed, April 21 | San Jacinto Day | United states (Texas) | State Holiday |
| Wed, April 21 | National Kindergarten Day | - | Weird |
| Wed, April 21 | National Chocolate Covered Cashews Day | - | Weird |
| Wed, April 21 | National Yellow Bat Day | - | Weird |
| Wed, April 21 | Administrative Professionals Day | United states | Observance |
| Thu, April 22 | National Earth Day | - | Weird |
| Thu, April 22 | National Girl Scout Leader’s Day | - | Weird |
| Thu, April 22 | National Jelly Bean Day | - | Weird |
| Thu, April 22 | National Take Our Daughters and Sons to Work Day | - | Weird |
| Fri, April 23 | St. George's Day | - | Christian |
| Fri, April 23 | World Book and Copyright Day | - | International |
| Fri, April 23 | National Talk Like Shakespeare Day | - | Weird |
| Fri, April 23 | National Picnic Day | - | Weird |
| Fri, April 23 | National Take a Chance Day | - | Weird |
| Fri, April 23 | National Cherry Cheesecake Day | - | Weird |
| Fri, April 23 | National Lost Dogs Awareness Day | - | Weird |
| Sat, April 24 | National Pigs in a Blanket Day | - | Weird |
| Sat, April 24 | National Rebuilding Day | - | Weird |
| Sat, April 24 | National Sense of Smell Day | - | Weird |
| Sat, April 24 | National Pool Opening Day | - | Weird |
| Sat, April 24 | National Kiss of Hope Day | - | Weird |
| Sun, April 25 | National Telephone Day | - | Weird |
| Sun, April 25 | National East Meets West Day | - | Weird |
| Sun, April 25 | National Zucchini Bread Day | - | Weird |
| Sun, April 25 | National DNA Day | - | Weird |
| Sun, April 25 | National Hug a Plumber Day | - | Weird |
| Sun, April 25 | National Pet Parents Day | - | Weird |
| Sun, April 25 | Mahavir Jayanti | India | Gazetted Holiday |
| Mon, April 26 | National Audubon Day | - | Weird |
| Mon, April 26 | National Dissertation Day | - | Weird |
| Mon, April 26 | National Richter Scale Day | - | Weird |
| Mon, April 26 | National Kids and Pets Day | - | Weird |
| Mon, April 26 | National Pretzel Day | - | Weird |
| Mon, April 26 | National Help a Horse Day | - | Weird |
| Mon, April 26 | National South Dakota Day | - | Weird |
| Tue, April 27 | Freedom Day | South africa | Public Holiday |
| Tue, April 27 | National Babe Ruth Day | - | Weird |
| Tue, April 27 | National Tell a Story Day | - | Weird |
| Tue, April 27 | National Prime Rib Day | - | Weird |
| Tue, April 27 | National Devil Dog Day | - | Weird |
| Tue, April 27 | Hanuman Jayanti | - | Hindu |
| Wed, April 28 | National Superhero Day | - | Weird |
| Wed, April 28 | National Blueberry Pie Day | - | Weird |
| Wed, April 28 | National Great Poetry Reading Day | - | Weird |
| Wed, April 28 | Workers’ Memorial Day | - | Weird |
| Wed, April 28 | National BraveHearts Day | - | Weird |
| Thu, April 29 | International Dance Day | - | Weird |
| Thu, April 29 | National Peace Rose Day | - | Weird |
| Thu, April 29 | National Zipper Day | - | Weird |
| Thu, April 29 | National Shrimp Scampi Day | - | Weird |
| Thu, April 29 | National Poem In Your Pocket Day | - | Weird |
| Fri, April 30 | St. James the Great Day | - | Christian |
| Fri, April 30 | National Bubble Tea Day | - | Weird |
| Fri, April 30 | National Sarcoidosis Day | - | Weird |
| Fri, April 30 | National Military Brats Day | - | Weird |
| Fri, April 30 | National PrepareAthon! Day | - | Weird |
| Fri, April 30 | National Honesty Day | - | Weird |
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| Fri, April 30 | National Adopt a Shelter Pet Day | - | Weird |
| Fri, April 30 | National Bugs Bunny Day | - | Weird |
| Fri, April 30 | National Hairstylist Appreciation Day | - | Weird |
| Fri, April 30 | National Oatmeal Cookie Day | - | Weird |
| Fri, April 30 | National Raisin Day | - | Weird |
| Fri, April 30 | National Hairball Awareness Day | - | Weird |
