The weather-based prediction model for brown planthopper (BPH), Nilaparvata lugens (Stal) was developed and validated using BPH sweep net catch data collected from Delhi during kharif 2017 and 2018. The BPH incidence started from 29th standard meteorological week (SMW) onwards (3BPH/20 sweeps) and attained its peak during 43rd SMW (213 BPH/20 sweeps) during kharif 2017. However, it declined thereafter and eventually disappeared after 47th SMW. The BPH sweep net catches revealed maximum and significant positive correlation with sun shine hours (SSH) of 2-lag week, and showed a significant negative correlation with evening relative humidity (RH2) and wind velocity (WV) of current and 1-lag week. On the other hand, BPH catches revealed a positive correlation with Tmax and morning relative humidity (RH1) of current, 1-lag as well as 2-lag week. Similarly, BPH catches had a negative association with Tmin and rainfall (RF) of current, 1-lag and 2-lag week. Of the weather factors RH1, RH2 and SSH were found to be the important factors that influenced BPH sweep net catches. The model was validated with the pest and weather data collected during kharif 2018 (R2 =0.733, RSME=2.16, MBE=-0.64 and MAE= 1.72.)