Clear nights radiate heat quickly. A mild afternoon can still produce frost by morning if wind drops and skies open — common after cold fronts in the UK.
Check overnight lows and the early hourly columns before an early commute. Road surface ice is about the coldest hours, not yesterday’s high.
Urban heat islands keep city centres a little milder than surrounding villages. If you pin both, expect the rural overnight to run colder.
Meridian does not replace local travel advisories; it gives you the temperature trend so you know when to look for them.
