First:

- April Fools Day

- Pesach begins (Passover)

Third:

- Founders Day (Vietnam)

- Farvardin (Iranian)

Fourth:

- Palm Sunday

Fifth:

- Ch'ing Ming Festival

- Arbor Day (Korean)

Sixth:

- Chakri Day (Thailand)

- Organization of the Church (Mormon)

Seventh:

- World Health Day (UN)

Eighth:

- Buddha's birth (c. 563-483 B.C.E.)

- Holy Thursday (Eastern Orthodox)

Ninth:

- Holy (Good) Friday

- Jalal (Baha'i)

Eleventh:

- Pascha (Easter) (Eastern Orthodox)

Thirteenth:

- Baisakhi (Hinduism, Sikhism, Bangladesh)

- Songkran/New Year (SE Asia Buddhists)

Fourteenth:

- Pan American Day (Latin America)

Sixteenth:

- Palm Sunday (Christian)

Seventeenth:

- First Muharram (Islam)

Eighteenth:

- Sechselaeuten begins (Switzerland)

- Akshaya-tritiya (Jainism)

Ninteenth:

- Passover (Jewish)

Twenty first :

- Good Friday (Christian)

- Feast of Ridvan begins (Baha'i)

- Kartini Day (Indonesia)

- Secretaries' Day

Twenty second:

- Earth Day

Twenty third:

- Yom ha-Shoah (Judaism)

- St. George's Day (Christian)

- Easter (Christian)

Twenty fourth:

- Martyrs Day (Armenian)

Twenty fifth:

- Anzac Day (Australian, New Zealand)

Twenty sixth:

- Arbor Day (USA)

- Ashura (Islam)

Twenty seventh:

- World Children's Day

Twenty eighth:

- National Day of Mourning (Canada)

- Jamal (Baha'i)

Thirtieth:

- Gahambar Maidyozarem (Zoroastrian)

- Beltane (Wicca)