The study is about testing the first phase of the new urban climate zoning scheme. The idea behind
this work is to test this scheme in a city that is in the developing world with all its antecedent environmental
and planning problems. This research tried to demonstrate a possible new approach to site classification using
a system of “Thermal Climate Zones”, and these zones were tested using the “urban” and “mixed” field sites
in Onitsha metropolis. The results show that Onitsha sites correspond well with Thermal Climate zones; the
zones observed include TCZ2 (old core), TCZ 3 (compact housing), TCZ 5 (Blocks), TCZ 6 (extensive
lowrise), TCZ 7 (Regular housing), TCZ 8 (shanty town), TCZ 9 (open grounds) and TCZ 20 (dispersed
settlements). Moreso, the major difference observed by the researcher is the difference in surface cover in some
categories or zones. The new system provides a more useful interpretation of the landscape for urban
climatologists. With further refinement, Thermal Climate Zones can improve consistency and accuracy in urban
climate reporting.