This is the region the old rules get most wrong. Lowland Inverness is the mildest mainland station we examined: milder than Edinburgh, because the sea moderates the coast and cold air drains off the hills. Nairn and the Moray coast share that mildness.
But the same region climbs into the Cairngorms, where frost runs weeks later; the upland figures use Braemar as the nearest long-record high station. Do not let "the Highlands are cold" cost you a Highland lowland spring.
Frost dates for Highlands
Half-month bands from named Met Office stations (1991-2020 averages). Lowland means coastal or under about 150m; upland is higher or inland.
| Garden | Last spring frost | First autumn frost | Safe to plant out | Season | Station | Confidence |
|---|---|---|---|---|---|---|
| lowland | late April | late October | mid May | ~180 days | Inverness | high |
| upland | late May to early June | mid-to-late September | mid June | ~115 days | Braemar (339m) | medium |
Upland: Braemar sits in postcode AB, but is the nearest long-record high-altitude Cairngorms station and is representative of Highland upland glens. The original spec's 'late May-early June' is correct for this ground — just not for the Highland coast.
Corroborated by Nairn, Wick Airport.
Sources: Met Office · Met Office
What this means for growing here
Sow and plant out to these dates rather than a UK calendar, and remember they are regional averages. Your own plot can run two to four weeks later in a frost pocket, or earlier against a warm wall. If your garden is high or inland, use the upland row; if it is coastal or low, the lowland one.The Planting Calendar turns these into a month-by-month plan.
Sources
- Met Office: location-specific long-term averages: the 1991-2020 air-frost day counts behind every variant row, including the Inverness/Edinburgh comparison
- Derivation method: GrowScotland's own. We treat a month as carrying meaningful frost risk when it averages at least half an air-frost day, take the last such month in spring and the first in autumn, and express each as a half-month band.