Unquestionably, the rapidly changing climate and, therefore, alterations in the associated bioclimate, constitute an alarming reality with implications for daily practice and natural capital management. This research displays the present and projected bioclimate evolution over Greece’s phytogeographical regions. For this purpose, ultrahigh-resolution computation results on the spatial distribution of the Emberger index’s Q2 classes of bioclimatic characterization are analyzed and illustrated for the first time. The assessments are performed over the reference period (1970–2000) and two future time frames (2021–2040; 2041–2060) under the RCP4.5 and RCP8.5 emission scenarios. By 2060 and under the extreme RCP8.5, intense xerothermic trends are demonstrated owing to the resulting significant spatial evolution mainly of the Arid–Hot, Semi-Arid–Very Hot, Semi-Arid–Hot, and Semi-Arid–Temperate Q2 classes, respectively, over the phytogeographical regions of Kiklades (up to 29% occupation), Kriti and Karpathos (up to 30%), West Aegean Islands (up to 26%), North East (up to 56%), and North Central (up to 31%). The RCP8.5 long-term period exhibits the strongest impacts over approximately the right half of the Greek territory, with the bioclimate appearing more dry–thermal in the future. In conclusion, the Emberger index provides an in-depth view of the Greek area’s bioclimatic regime and the potential alterations due to climate change per phytogeographical region.