The new year starts in spring. A Hindu calendar is also referred to as Panchanga (पञ्चाङ्ग). The complete calendar contain five angas or parts of information: lunar day (tithi), solar day (diwas), asterism (naksatra), planetary joining (yoga) and astronomical period (karanam). This structure gives the calendar the name Panchangam.
There are 12 months in the lunar calendar. A month contains two fortnights called pakṣa (पक्ष, meaning "side"). One fortnight is the bright, waxing half where the moon size grows and it ends in the full moon. This is called Shukla Paksha. The other half is the darkening, waning fortnight which ends in the new moon.
Twelve Hindu months are equal to approximately 354 days, while the length of a solar year is about 365 days. This creates a difference of about eleven days.
2. Jyeshta: May - June
Ganga Dussehra, Nirjala Ekadashi, Vat Purnima Vrat
3. Āshada: June - July
4. Shraavana: July - August
Hariyali Teej, Raksha Bandhan
10. Magha: January - February
Jaya Ekadashi, Magh Purnima, Shattila Ekadashi
The longitude of the sun and the longitude of the moon are added, and normalized to a value ranging between 0° to 360°. This sum is divided into 27 parts. These parts are called the yogas.