First Frost Dates in the UK by Region

The first frost of autumn is the night that ends the growing season for tender crops. Tomatoes, courgettes, beans, dahlias and chillies outside are blackened by it, while hardy veg like kale and leeks carry on regardless. Knowing roughly when it usually arrives where you live tells you when to pick, lift, cover and bring things in.

This guide gives the typical first-frost window for each UK region, the Met Office averages behind the picture, and what makes one night frosty and the next one not. For your own region with a countdown and this week's jobs, use the first frost checker.

Typical first-frost windows by region

The dates below come from the same regional table as the frost date checker. Each one is typical (approximate): a single day would claim more precision than an average can carry, so each region gets a three-week window centred on its typical date. Your own garden can sit either side of it.

All dates are typical (approximate). The broad pattern holds: the north and Scotland get frost first, then northern England, then Wales, the Midlands and the south. The mildest places, like the far South West coast, can go much later, while high ground anywhere is frostier than the regional average.

If your window has already opened, frost is possible on any clear, still night from now on. The jobs to do before then are in what to do before the first frost.

What the Met Office averages show

The Met Office publishes long-term averages for its weather stations, including the average number of days of air frost in each month: days when the air temperature falls below 0°C. These are monthly counts over 1991–2020. They don't give a first-frost date, but they show how the frost season builds and fades in each part of the country.

Here's one station per region, September to May. A figure of 1.00 means one frosty day in that month in an average year; a figure below 1 means some years get a frost that month and most don't.

Source: Met Office location-specific long-term averages, 1991–2020, mean days of air frost.

Three things stand out.

• October is the turn of the year for most of the UK. Every station except Cardiff, Camborne and Heathrow averages at least one air frost in October. At Aviemore it's already more than four.
• Where you are inside a region matters as much as the region. Yeovilton in inland Somerset averages 48.62 frosty days a year; Camborne on the Cornish coast averages 7.38. Both are in the South West.
• Towns are milder. Heathrow, on the edge of London, averages 26.99 a year, the lowest of these stations apart from Camborne.

What makes a frosty night

Frost doesn't arrive on a date: it arrives on a particular kind of night. Once you know the signs, the forecast makes far more sense.

Clear skies. Through the day the ground soaks up warmth from the sun. After dark it gives that warmth back to the sky. Cloud acts like a lid and sends some of it back down, so a cloudy night stays milder. On a clear night the heat escapes straight up, and the ground, and the plants on it, cool fast.

Still air. Wind keeps stirring the air, mixing in warmer air from higher up. When the wind drops, the coldest air settles in a thin layer right at ground level, exactly where your plants are.

A cold air mass. A frost is more likely after a northerly wind has brought colder air in. A clear, still evening after a cold, bright day is the classic first-frost set-up.

So when the evening forecast says clear skies, light winds and a low in single figures, treat it as a frost warning for exposed plants, even if the official minimum stays above freezing. The ground and leaves get colder than the air a little above them.

Frost pockets, towns and coasts

Cold air is heavier than warm air, so on a still night it drains downhill like water and collects in the lowest ground. A garden at the bottom of a slope, in a valley or in a hollow is a frost pocket: it gets more frosts, earlier in autumn and later in spring, than gardens a short way up the hill. A solid fence or hedge across the bottom of a sloping garden can trap cold air behind it and make its own small frost pocket.

The opposite is also true. Towns and cities hold heat in their buildings and roads, so urban gardens usually get fewer frosts than open countryside nearby. Gardens close to the sea benefit from the water, which cools down slowly in autumn. High ground is colder than low ground almost everywhere.

If your garden is a frost pocket or on high ground, plan as if your first frost comes at the early end of your region's window, or before it. In a sheltered town garden near the coast, you may get a little longer.

How to use your first-frost date

Use the typical date to plan, and the forecast to act.

• Two to six weeks before your window: get your fleece and cloches out and check them, decide where tender pots will spend the winter, and line the greenhouse if you're keeping plants under glass. The checklist is in what to do before the first frost.
• In the last fortnight: pick the last tender crops, bring in plants you want to keep, and keep fleece by the door.
• From the window onwards: check the evening forecast. On clear, still nights, cover tender plants before dusk. How to do that well is in how to protect plants from frost.

Not sure which of your plants actually mind? Hardy or tender? explains the difference and the RHS hardiness ratings. Pots need their own care, because roots in a container are far more exposed than roots in the ground: see protecting pots and containers from frost.

The last frost works the same way

Everything here applies in reverse in spring. The typical last spring frost is the date tender crops can safely go outside, and it's on the same table above. The Met Office averages show why gardeners in the north wait: Aviemore still averages 3.39 frosty days in May, Durham 0.80 and Sutton Bonington 0.87. A late frost after a warm spell is what catches out early planting.

The frost date checker shows both dates for your region, works out your sowing and hardening-off dates from the last frost, and can add them to your calendar.