The primary concern with LAMP/WordPress sites is the memory usage rather than the CPU. Since droplets do not have swap space by default, if the MySQL process uses up the available memory it can crash.

Currently the graphs do not include memory usage but you can track this yourself. The command free -m will output your current used/available memory. If you wanted to you could set up a cron job to run the following:

date >> /some/directory/memory.log
free -m >> /some/directory/memory.log

Each time this command runs it will append the output to what was previously there starting with the current timestamp and then including the memory use details.

I would recommend monitoring memory use for a couple days at least before deciding whether to scale down your droplet. In most cases a 1GB droplet will support WordPress well.