[33][34][35][36] In the modern era, while it is observed as a secular holiday by most celebrants, Nowruz remains a holy day for Zoroastrians,[37] Baháʼís,[38] and Ismaʿili Shia Muslims.

[27][42] Customs for the festival include various fire and water rituals, celebratory dances, gift exchanges, and poetry recitations, among others; these observances differ between the cultures of the diverse communities that celebrate it.

[53][54] Iranians sing the poetic line "my yellow is yours, your red is mine", which means "my weakness to you and your strength to me" (Persian: سرخی تو از من، زردی من از تو, romanized: sorkhi-ye to az man, zardi-ye man az to) to the fire during the festival, asking the fire to take away ill-health and problems and replace them with warmth, health, and energy.

Spoon banging (قاشق زنی, qāšoq zani) is a tradition observed on the eve of Charshanbe Suri, similar to the Halloween custom of trick-or-treating.

In Azerbaijan, children slip around to their neighbors' homes and apartments on the last Tuesday prior to Novruz, knock at the doors, and leave their caps or little basket on the thresholds, hiding nearby to wait for candies, pastries and nuts.

On the thirteenth day of the New Year, Iranians leave their houses to enjoy nature and picnic outdoors, as part of the Sizdah Bedar ceremony.

The Shahnameh credits the foundation of Nowruz to the mythical Iranian King Jamshid, who saves mankind from a winter destined to kill every living creature.

Since the communal observations of the ancient Iranians appear in general to have been seasonal ones and related to agriculture, "it is probable that they traditionally held festivals in both autumn and spring, to mark the major turning points of the natural year.

The Iranian festivals such as Mehregan (autumnal equinox), Tirgan, and the eve of Chelle ye Zemestan (winter solstice) also had an origin in the Sun god (Mithra).

Among other ideas, Zoroastrianism is the first monotheistic religion that emphasizes broad concepts such as the corresponding work of good and evil in the world, and the connection of humans to nature.

According to Mary Boyce,[60] "It seems a reasonable surmise that Nowruz, the holiest of them all, with deep doctrinal significance, was founded by Zoroaster himself"; although there is no clear date of origin.

In the section on the Iranian calendar, he mentions Nowruz, Sadeh, Tirgan, Mehrgan, the six Gahambars, Farvardigan, Bahmanja, Esfand Armaz and several other festivals.

[67] It has been suggested that the famous Persepolis complex, or at least the palace of Apadana and the Hundred Columns Hall, were built for the specific purpose of celebrating a feast related to Nowruz.

[68] A specific novella is not identified and Encyclopedia Britannica itself notes that "no Jewish texts of this genre from the Persian period are extant, so these new elements can be recognized only inferentially."

In his Shahnameh, the tenth-century poet Ferdowsi narrates a fictional account of Darius III's death, where an injured Darius, with his head cradled on Alexander the Great’s thigh, asks Alexander to wed Roxana, so their children might uphold Nowruz and keep the flame of Zoroaster burning: Her mother named her Roxana the fair; The world found joy and solace in her care.

The Iranian Buyid ruler 'Adud al-Dawla (r. 949–983) customarily welcomed Nowruz in a majestic hall, decked with gold and silver plates and vases full of fruit and colorful flowers.

In 1079 CE during the Seljuq dynasty era, a group of eight scholars led by astronomer and polymath Omar Khayyam calculated and established the Jalali calendar, computing the year starting from Nowruz.

The festival along with Mehregan was widely celebrated in Al-Andalus, as the Andalusians from the 9th century onwards strongly identified with many Iranian traditions despite the opposition from the Maliki jurists.

People start preparing for Nowruz with a major spring cleaning of their homes and by buying new clothes to wear for the New Year, as well as the purchase of flowers.

Typically, before the arrival of Nowruz, family members gather around the Haft-sin table and await the exact moment of the March equinox to celebrate the New Year.

[88] Haji Firuz, a character with his face and hands covered in soot, clad in bright red clothes and a felt hat, is the companion of Amu Nowruz.

He is an old, bearded man wearing colorful clothes with a long hat and rosary who symbolizes beneficence and the power of nature yielding the forces of winter.

[111] It is a religious ceremony performed at the Blue Mosque of Mazar-i-Sharif by raising a special banner resembling the Derafsh Kaviani royal standard.

In the festival of Dehqān (Dari: دهقان, 'farmer'), also celebrated on the first day of the New Year, farmers walk in the cities as a sign of encouragement for the agricultural production.

In the Emirate of Bukhara, a broad official celebration of Nowruz was started by Amir Muzaffar, who sought to strengthen the image of the Manghyt dynasty during the crisis of political legitimacy.

[130] Georgian politicians have attended the festivities in the capital over the years, and have congratulated the Nowruz-observing ethnic groups and nationals in Georgia on the day of Nowruz.

[135] A popular Deccani Urdu poem written by the founder of Hyderabad, Muhammad Quli Qutb Shah, is recited in the Deccan region on Nauroz: کہ نس دن عید ہور نوروز منج کوں نت خدا دیتا مرے دل مرغ کی خاطر پھولاں عشرت نوا دیتا The way God has given me Eid and Nauroz forevermore The flowers give the birds of my heart bliss and joy galore Nowruz is a two-week celebration that marks the beginning of the New Year in Iran's official Solar Hijri calendar.

[159] The holiday celebrates the arrival of the spring which Zoroastrians see as a representation of the triumph of good (Asha) over evil (Druj), a central theme of the religion.

[161][163] Baháʼu'lláh, the founder of the Baháʼí Faith, explained that Naw-Rúz was associated with the Most Great Name of God,[161][163] and was instituted as a festival for those who observed the Nineteen-Day Fast.

[174] However, Prominent Twelver clerics like the Ayatollahs Ruhollah Khomeini and Ali Khamenei have also disparaged the actual holiday of Nowruz, condemning its origins in Zoroastrianism.