Flood warnings could be put in place around the region's coasts as the South West anticipates some of the highest tides of the year.
A combination of the tides and the weather can cause flooding
This weekend the autumn equinox clashes with the usual spring tides and it could cause flooding if there is also stormy weather.
This happened in October 2004 when a severe flood warning was put in place from Land's End to Plymouth.
The Environment Agency says it is monitoring conditions.
The agency said flood defences were designed to take account of this period and it is not currently expecting any problems.
"The weather is a major influence on whether the tides will cause flood problems," said Tim Wood from the agency.
"However, it is important that everyone living on the coast or in a tidal area is aware of the risk and is prepared.
He said simple preparations can make a "big difference".
"It's far too late to start thinking about it when the water is lapping at your front door, so start preparing for it now," he said.