Spring is set to return towards the end of this week with forecasters predicting sunshine and 20°C on Thursday.
The start of the week is set to remain chilly with a possibility of morning frost on Tuesday, with a low temperature of -3°C in west Wales overnight.
There will be widespread sunshine on Tuesday and prolonged blue skies, but with a chilly wind, with temperatures remaining at the seasonal average of 10°C.
Wednesday will herald a change however with lighter winds heading in from the south.
Thursday will be the best bet for warm weather with the Met Office predicting the mercury will hit 20°C in Aberystwyth, but sunshine may be accompanied in places with wispy cloud.
Looking ahead to Friday and the weekend, the Met Office says: "Still fine for many at the start of this period but by Friday and into the weekend, there is an increasing likelihood that rain or showers will start to arrive from the south or west.
"Wetter weather will probably spread to all areas, at least for a time and could be accompanied by strong winds at times.
"Into the following week, unsettled conditions will probably continue across many parts of the UK.
"Some heavy rain or showers are possible at times, these most likely across southern parts of the country.
"Temperatures are likely to be widely above average at the start of this period before probably falling back and then fluctuating around average for the remainder of the period."
Thursday's warm weather coincides with the spring equinox, which marks the start of astronomical spring.