Plum prefers temperate climate however, it has been found growing from higher hills in Srinagar to Jaipur in Rajasthan. Kala Amritsari, Satluj Purple and Titron cultivars of plum planted at experimental orchard of CCS Haryana Agricultural University, Hisar farm in the year 2001 on which the present study was done during the year 2013-14. The overall growth was observed better in Kala Amritsari followed by Satluj purple and Titron which is a late maturing variety. The thermal time required by Kala Amritsari and Satluj Purple was at par but the Titron required more thermal indices. The heat use efficiency was observed highest for Kala Amritsari and lowest for Titron whereas the photothermal index was highest in Titron followed by Kala Amritsari and Satluj Purple. The thermal units explained the 94 per cent variation in fruit yield of Kala Amritsari, 87 per cent variation in Satluj Purple and 83 percent variation in fruit yield of Titron cultivar.