The quality of monitoring activities based on a manager-agent model is challenging when monitoring large-scale environments. Today, the size of these environments is becoming more and more important and it has a considerable impact on the performance of a monitoring system. In particular, the temporal synchronisation between the real and inferred views of a monitored system. The inferred view is provided by the manager from the data collected from agents. In this paper, we analyse the delays that experience monitoring data when they are transfered from agents to the manager. These delays may alter the inferred view since monitoring data becomes outated. Therefore, we investigate the statistical properties of these delays and their variations when the number of monitoring agents increases. Monitoring delays are measured from our benchmarking platform dedicated to the JMX monitoring framework.