You can read the significance of Ugadi and ugadi pachadi in Ugadi Subhakamskhalu!
Ugadi begins on Suklapaksha Padyami day in Chaitra maasam.
Ugadi or commonly said Samvathsaradi as the name says it is the beginning of new era, the season of spring is associated with this lunar based festival. Ugadi is the New Year for the Telugu, Kannada, Marathi and Sindhi speaking people around the world. Most of the countries around the world celebrate their New Year based on lunar cycle, unlike the Gregorian Calendar. I would like to put here what I know about how the Hindu lunar calendar is read. This is my basic understanding.
Kali'yugam - 1200 divya-samvatsaralu
1 Divya samvatsaram-360 samvasthsaralu
60 samvathsaralu names-Prabahva to Akshaya
Jaya nama samvathsaramu (March 31, 2014-March 21, 2015)
1) Uttarayanam 2) Dakshinayanam
Ruthuvulu (seasons) (6) - maasamulu (months) (12)
Vasantha ruthuvu - Chaitra maasam, Vaisakha maasam
Grishma ruthuvu - Jyesta maasam, Ashada maasam
Varsha ruthuvu - Sravanam, Bhadrapada
Sarad ruthuvu - Aswayuja maasam, Karthika maasam
Hemantha ruthuvu - Margasirsha maasam, Pushya maasam
Sashir ruthuvu - Magha maasam, Phalguna maasam
Maasam - 2 pakshalu (fortnights) Sukla paksham (waxing moon phase), Krishna paksham (waning moon phase)
Thidhi (days) – Padyami, vidiya, thruthiya, chavithi, panchami, sashti, sapthami, ashtami, navami, dasami, ekadasi, dwadasi, thrayodasi, chaturdasi, pournami (full moon); the first 14 days repeat and the month concludes with amavasya (no moon day).
Welcome the New Year with complete anticipation, hope and eagerness. Look forward to a bountiful year of prosperity, satisfaction and peace. Have a very happy Ugadi!