Cockroaches are generally not active during the day.
More Info: Generally speaking, cockroaches are not active during the day. At that time, they display thigmotropic behavior, that is, hiding in a crevice or another place where they can safely nestle into an area that provides contact on both their front and backsides, or top and bottom.
In fact, one of the best ways to convey the 24-hour cycle of the average household cockroach is to imagine what their point of view is like. From roughly 2 a.m. to 10 p.m. local time, they are hidden away somewhere, sleepily passing the time. However, once the lights go out, they spring to life, foraging for food for the next four hours.
Managed Environments and Daytime Sightings
About the only place where cockroaches might be seen taking on a consistent cycle of activity during the day is in managed environments such as zoo reptile houses. In these environs, the lights are kept low, the humidity is set high, and as such, this artificially sustained environment blurs the cycle of normal day-night activity.
Cockroaches are extremely efficient when it comes to putting those nightly four-hour cycles to work. In one instance, a scientific survey of their activity found that they were able to gather enough food during a single night to sustain them through six full days. The presence of cockroaches in a home during the day is a definite alarm bell, as it usually signals the presence of a very large population.
Most Active During Procreative Cycle
Female German cockroaches, part of the most common household species, may be particularly active during this nightly four-hour window at the beginning of their procreative cycle. They carry an egg case around for several days before dropping it into a safe hiding area. Corrugated cardboard is one of their favorite surfaces for this purpose, since they can easily burrow a hole and then spit out the pieces they have chewed to cover up the hole. It takes up to 18 days for the eggs to hatch.
University of Massachusetts – Cockroaches FAQ, Retrieved September 23, 2010 from http://www.bio.umass.edu/biology/kunkel/cockroach_faq.html
University of Rhode Island – Cockroaches, Retrieved September 23, 2010 from http://www.uri.edu/ce/factsheets/sheets/cockroaches.html