A 32 month long nighttime ambient sound level survey was conducted between from April 2017 and December 2019, inclusive. Sound level data was recorded at three locations within approximately 600 m of one another. Weather data was collected at one site. The measurement locations were at the edge of the city, where the suburbs make way for the countryside. Two noise monitoring stations were located near the back yards of detached houses. The third station was located in a more rural setting. This paper will look at trends in the nighttime ambient sound level (e.g. summertime vs wintertime), and try to establish the minimal duration of a measurement program for generating reliable results.