"frequent rain" is correct and can be used in written English.
You can use it when you're describing the weather in a particular area or during a certain season, such as: "The area is known for its frequent rain during the fall and winter months."
Thus, the low pH in SN 3, 4 and 24 could indicate that those areas receive frequent rain recharge which locally has low pH or are frequently pumped and hence less conc. of dissolved minerals (Napacho and Manyele 2010).
"If there is frequent rain, they get washed away".
Except for frequent rain and fog, "It's just dreamy," he said with a sigh.
All areas had frequent rain but northern and western areas were extremely wet, especially on high ground.
These images were mostly of Ireland, where she had recently travelled with a friend: the emerald countryside, the frequent rain.
It has been characterised by frequent rain systems tracking across the south of Britain, often associated with high winds.
Because of frequent rains, the rivers flood.
The Roman historian Tacitus recorded that the climate was "objectionable, with frequent rains and mists, but no extreme cold".
The heaviest precipitation occurs during the autumn months (March and April), although more frequent rains occur in winter.
Officials with the city's Department of Environmental Protection say that more frequent rains over the last two years have stirred up sediment that washes into the Ashokan Reservoir's two basins.
Images of Mars's crescent dunes, for instance, reveal information about its winds, and its tree-like drainage systems chronicle a time when the planet, now arid and silent, had frequent rains and babbling brooks.
