The Met Office has issued another yellow warning for fog later.
Forecasters said fog patches will reform during Thursday afternoon, particularly in river valleys and near lakes, and may become locally dense during the evening with visibility below 100 m in places.
Fog is expected to become more widespread overnight and after dawn on Friday morning with further dense patches, before slowly clearing. However, a few patches may persist into the afternoon.
The warning will come into force across Herefordshire, Monmouthshire, Worcestershire and Shropshire from 5pm today until 11am tomorrow.