Planning ahead: When can we expect the first frost?

With cooler air on its way from the north in the coming days, you might be wondering when we could expect the first frost of the autumn season.

The average first frost for many inland areas in the UK and Ireland is within the first ten days of November, but with some parts of Scotland up to a month earlier. Generally the further north you are, the earlier the frost.

Frost commonly forms on a clear night when the temperature of a surface, such as the ground or your car, falls below zero, and then below the dew point so that moisture can be deposited as frost.

Under clear skies and light winds, the ground temperature can drop a few degrees lower than the air temperature, though this is more difficult at the start of the season when the ground is still holding residual warmth from the summer.

Jack Frost had a bit of a head start in the Scottish Highlands in August, with a grass frost reported on a few occasions. But as for an autumn frost, there is a decent chance across parts of Scotland throughout the weekend, with overnight minimum air temperatures expected to be 1-4C quite widely.

Friday September 16th looks to be the chilliest of the coming nights, with a risk of a localised frost across northern England, particularly in sheltered spots of the Pennines, where air temperatures could get to zero. Rural spots across south-east Ireland and the Welsh mountains may also be at a slight risk.

However, with a a brisk wind expected particularly along the north and east coast, in addition to coastal areas remaining warmer than inland spots thanks to the warmth of the sea during this time of year, this lessens the chance for these areas. As for anywhere further south in England, the risk of the first frost still appears to be a while off.

Keep an eye on our TemperatureRadar in the coming days, and also for tips coming soon on how to protect your tender plants as it turns colder.