The last frost in the UK, and why it decides your sowing dates
Short answer
In lowland England and Wales the average last frost falls around mid to late April. It comes earlier near the south and west coasts and in big cities, and later in northern England, Scotland, on high ground and in frost pockets, where May frosts are common. An average date is a midpoint, not a promise.
For most of lowland England and Wales, the last spring frost usually comes somewhere around mid to late April. In Scotland, northern England and on high ground it’s often well into May, while the mildest coastal gardens in the south-west can be clear by late March or early April.
Those are averages. The real date moves every year, and your own garden can differ from a town a few miles away.
What a frost date actually means
The average last frost date is the point in spring after which, in a typical year, you won’t see another air frost. The average first frost date is the same idea in autumn: the first night it drops to 0 °C or below.
The gap between the two is your frost-free season. In lowland England and Wales that’s roughly the end of April to the end of October, about six months. Further north and higher up it’s shorter, and that’s the main reason Scottish growers can struggle with crops like squash and sweetcorn that need a long, warm run.
Typical last frost by area
These are broad ranges, not station records. Treat them as a starting point and adjust once you know your own plot.
| Area | Usual last spring frost | Usual first autumn frost |
|---|---|---|
| Cornwall, Scilly, south-west coasts | Late March to early April | November or later |
| Central London and big cities | Early to mid April | Early to mid November |
| Lowland England and Wales | Mid to late April | Around the end of October |
| Northern England, inland Wales | Late April to early May | Mid to late October |
| Lowland Scotland | Early to mid May | Early to mid October |
| Highlands, high ground, frost pockets | Mid May to early June | September to early October |
Coasts stay milder because the sea holds its warmth. Cities do the same thanks to buildings and tarmac. Height works the other way: the higher you are, the colder the nights.
Why the average isn’t a guarantee
An average is a middle value. In a fair number of years there will be a frost after it, sometimes by two or three weeks. A clear, still night in May with a high-pressure system overhead can drop well below zero even after a run of warm days.
Your own garden adds its own twist. Cold air is heavy and runs downhill, so it pools in valley bottoms, at the foot of slopes and against walls or hedges that block its path. These frost pockets can be several degrees colder than a garden higher up the same road. A south-facing wall, on the other hand, can keep the ground near it frost-free for longer.
Ground frost is worth knowing about too. Soil and grass lose heat faster than the air, so a ground frost can form on nights when the forecast air temperature stays at 1 or 2 °C. Low seedlings feel that first.
How to find your own frost dates
- Start with your area. Use the table above, or the frost dates from a local allotment society or gardening club, who usually know the local quirks.
- Look at the last few years. Weather records for your nearest town show when the last frost actually fell. Several years together tell you far more than one.
- Watch your own plot. Note the first and last mornings you see frost on the grass, the car or the shed roof. After two or three seasons you’ll know whether you’re earlier or later than the area average.
- Check the forecast every spring. Whatever the average says, a forecast frost in the next few days overrules it.
VegLog works out average frost dates for your own town from the last few years of Apple Weather data, so the sowing dates in the app start from your local figure rather than a national one.
How gardeners use frost dates
Most sowing advice is really counted from the last frost, which is why it works across the country once you shift it to your own date. Using a last frost of around 20 April, typical of lowland England and Wales:
| Crop | What to do | Timing |
|---|---|---|
| Chillies | Sow indoors | 12 to 6 weeks before last frost (late January to early March) |
| Tomatoes | Sow indoors | 8 to 4 weeks before last frost (late February to late March) |
| Peas | Sow outdoors | From 6 weeks before last frost (early March) |
| Carrots | Sow outdoors | From 4 weeks before last frost (late March) |
| Courgettes, squash, sweetcorn | Sow indoors | 3 weeks before to 1 week after last frost |
| Tomatoes, courgettes, runner beans | Plant out | From 2 weeks after last frost (early May) |
Hardy crops such as peas, broad beans and onions can take a light frost, so they go in before the last frost date. Tender crops like tomatoes, courgettes, beans and sweetcorn are killed by any frost, so they wait until a couple of weeks after it. That buffer is there because of the late frosts described above.
If your last frost is a fortnight later than 20 April, move every date in the table two weeks later. The same goes for the autumn frost date and late sowings: last sowings of French beans, for example, need about 12 weeks before the first autumn frost to crop.
Common mistakes
- Planting out on the average date itself. It’s a coin toss. Give tender plants another two weeks, and harden them off for a week or so first.
- Trusting a warm April. A sunny week doesn’t mean the frosts are over. Watch for clear, still nights.
- Forgetting the low spots. If your bed sits at the bottom of a slope, it may be your coldest corner, even in a mild area.
- Leaving fleece in the shed. Keep some to hand from April to the end of May for unexpected cold nights.
Questions people also ask
Can you get a frost in May in the UK?
Yes. Frosts in early and mid May are not unusual, especially in the north, on high ground and in low-lying gardens. That's why tender plants such as tomatoes and courgettes usually go out a couple of weeks after the average last frost.
When is the first frost of autumn in the UK?
In lowland England and Wales the first air frost usually arrives around the end of October. Northern and upland gardens can see one in early October, while sheltered coastal and city gardens may stay frost-free into November or later.
What temperature counts as a frost?
A frost is when the temperature drops to 0 °C or below. An air frost is measured a little above the ground; a ground frost forms on grass and soil, which can freeze on nights when the air stays just above zero.
Does fleece protect plants from frost?
A layer of horticultural fleece gives a couple of degrees of protection on a light frost, enough to save hardy and half-hardy seedlings. It won't reliably save tender crops in a hard frost, so bring those under cover.
Dates set to your own frost dates
VegLog works out sowing and planting times for your town, then reminds you when each job is due.
