The official Iranian time will change once at the beginning of the Iranian calendar year (which started on March 20 this year), and once again at the start of the second half of each year.
Daylight Savings Time - DST - also known as Summer Time - has the ultimate goal of saving energy. It involves adjusting the official local time forward during the summer months, for a fuller utilization of sunlight. Observation of local time is then adjusted to better reflect natural time - the sun - for winter.
The Iranian New Year also starts with Nowruz celebrations.
Nowruz, which coincides with the first day of spring on the solar calendar, is mostly celebrated in Iran, Afghanistan, Azerbaijan, India, Kyrgyzstan, Tajikistan, Pakistan, Turkey and Uzbekistan.
The International Day of Nowruz was registered on the UNESCO List of the Intangible Cultural Heritage of Humanity on February 23, 2010.
For Iranians, Nowruz is a celebration of renewal and change, a time to visit relatives and friends, and pay respect to senior family members.
Iranians welcome the New Year by wearing new clothes and setting the Haft Seen, a table containing seven items starting with the letter 'S'; Sabzeh (freshly grown greens), Samanu (sweet wheat paste), Senjed (jujube), Seeb (apple), Seer (garlic), Serkeh (vinegar) and Somaq (sumac).