Continuously vs. continually

Question:

I can never figure out the difference between continuously and continually. Is there one? If so, what is it?

Answer:

Technically, there is a difference between these two adverbs, but most usage guides admit that this nuance is often ignored. In formal writing, however, it should definitely be observed.

Continuously means that the action occurs without break. The action typically happens over a long period of time (as in months or years), but doesn't necessarily have to. Video surveillance, evolution and breathing are some examples of things that occur continuously.

Continually means that the action occurs repeatedly, but with intermittent breaks. Traffic, war, and work are examples of things that could happen continually.

For example:

• The traffic surveillance camera taped continuously as the cars continually moved past.