^ The OP said that the input is fed by an LM35 which is a Centigrade temperature sensor.
If the purpose of the circuit is to have a visual indication of temperature, the presence of D5 will degrade accuracy. This is because because the forward drop
1) has tolerance, that is, it varies between individual samples
2) is not constant even for the same sample. It's a function of the diode V-I curve
3) varies with temperature
If the diode is included with the intention of raising the minimum scale, that could easily be done by using apprpriate values for the voltage divider chain R8-R12.