As Chiglet says, runway surface condition is reported in thirds. The surface condtions are reported as 'dry, damp, wet, water patches, flooded etc...' Anything worse than 'wet' is considered to be a contaminated surface and imposes severe operating limitations, if permitted at all.
Each operator and aircraft manufacturer will have their own rules as to how to respond to this; some will say that any third reported as 'wet' requires an adjustment of braking setting accordingly both for arrival and rejected take-off. It may also impose greater cross-wind limitations, too.
Any respectable length of runway is quite likely to have different conditions along its length in showery conditions; we often report 'dry, damp, wet' or any combination you like! Fortunately our cambered grooved asphalt surface drains extremely well and we never go beyond 'wet, wet, wet' even in a summer downpour.
Some runways are notified as 'liable to be slippery when wet'; quite an embarrasment, especially when you've just spent millions on having it resurfaced.
The Odd One.