Haemonchosis is an evergreen threat to small ruminant production in tropics. Number of abiotic and biotic factors influences the seasonal incidence of haemonchosis in small ruminants. There was an outbreak in rainy season of October, 2016 to January, 2017 on young adult goats. From various meteorological agencies 12 relevant risk factors were chosen randomly and their influence was analyzed. Among the risk factors, relative humidity influences positively and maximum day temperature influences in negative way. The mean maximum day temperature in outbreak months was 29.5ºC whereas in rest of the months it was 34.6 ºC. Similarly there was an increase in mean relative humidity (84%) when compared to rest of the months (71%). Increase in mean relative humidity for about 13% and a decrease in mean maximum day temperature for about 5.1 ºC were the reasons for this outbreak. 92.9% of cases were correctly classified between outbreak and non – outbreak groups based on standardized canonical discriminant analysis. We conclude that increase in mean relative humidity (13%) and decrease in mean day time maximum temperature (5.1oC) determines hemonchosis outbreak when compare various other metrological parameters.