Over the last fifty years, the wheat improvement programs and releasing commercial wheat varieties in south Asia has been successful in developing countries. However, a decrease in annual genetic gain for yield has been observed attributed to global warming. A decline in wheat productivity was observed between 7-21% in Indian Punjab during 2009-10 crop season, and again in 2014-15 in whole of North-West India. Being a winter cereal, wheat needs substantial amount of heat tolerance both at early growth stages, immediately after planting and at terminal grain filling stage. Significant variation for terminal heat tolerance exists in the native wheat gene pool. Likewise, early sowing may allow to select early heat tolerant genotypes along with longer phenology to escape terminal heat stresses. A study was conducted to map early heat tolerance at BISA farm, Ludhiana in 2017-18 and 2018-19 seasons. A total of six hundred wheat lines were planted seventeen days earlier than timely planting for 2017-18 season and, another set of six hundred lines were planted 24 days earlier than timely planting for 2018-19 season. Trial design was alpha lattice with two replications. Several agro-morphological and physiological traits were evaluated. Yield was significantly increased but the TGW was shown to be varied in both the years. Most of the early planted genotypes matured one week earlier in 2017-18 season and two weeks earlier in 2018-19 season than normal planting, pertaining that the addition of phenological times is dissecting its effect on other phenological dates. We performed Genome Wide Association Studies (GWAS) and identified several significant SNP markers associated with early heat tolerance. The results open new avenue to further study QTLs association in details with adaptation to early planting through phenological genes like vernalization, photoperiod, reduced height and earliness per se.