Field experiments were carried out in two seasons (2020 and 2021) to investigate the population fluctuation of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) under some selected climatic factors [temperatures in (°C): Maximum Temperature (Max.T) and Minimum Temperature (Min.T); temperature in the soil (°C): Soil Maximum Temperature (SMax.T) and Minimum Temperature (SMin.T); relative humidity in (%): relative Maximum humidity (RMax.H) and Minimum humidity (RMin.H); wind speed in (Km/hr.): maximum wind speed (Max.ws) and Minimum wind speed (Min.ws)]. as well as tomato age. The population grew gradually, reaching four peaks in the first season and five in the second, with the infestation starting on March 7th, fifteen days after the transplant date. March and April marked the high points of both seasons, with a minor decline in infestation in May and June until the end of the season. There is a clear and substantial negative association between the T. absoluta population (mean number of larvae per 10 plants per replicate) and plant age, air temperatures (Max.T and Min.T), and soil temperatures (SMax.T and SMin.T). On the other hand, the population of T. absoluta exhibited a non-significant positive correlation with the minimum humidity (RMin.H) and a significant positive correlation with the maximum humidity (RMax.H). Lastly, the population of T. absoluta showed a non-significant positive connection with wind speed (Max.ws and Min.ws).