There are different types of temperatures such as:

Air temperature
Mean radiant temperature
Environmental temperature
Dry resultant temperature

As far as I know Ecotect (by default) calculates the dry resultant temperature and accordingly calculates the heating and cooling loads. However, it can calculate the loads using only the internal temperatures if one check 'Use more proactive DBT-based heating and cooling load algorithm' under the Analysis Settings under the User preferences. Why there is a note saying (Values shown are environment temperature, not air temperature) at the top left hand corner of the hourly temperature graph? Does this means that the temperature that Ecotect presents in this graph is Environmental temperature but it uses either the air temperature or the dry resultant temperature to calculate the heating and cooling loads?

The hourly temperatures section in the help says: (Hourly temperature graphs display the internal temperatures of all visible thermal zones in the model over a 24-hour period).