A regional average is not the plot minimum
Cold air can collect in a hollow while a nearby slope or urban wall remains warmer. A coastal location can avoid some severe lows yet stay too cool and windy for tender crops.
Distinguish ground frost from air frost
Surfaces can fall below freezing even when the forecast air temperature remains above zero. Use current local information and direct observation rather than one monthly threshold.
Count the warmth needed after planting
Being able to plant is not the same as having enough season to ripen a tomato, pumpkin, sweetcorn or aubergine. Compare cultivar maturity, soil warmth and likely autumn exposure.
Use temporary protection safely
A cover must be stable, ventilated, kept away from heaters or flame and removed when it overheats or catches wind. Protection reduces some exposure; it does not create a guaranteed climate.
Sources, scope and limits
Sources support the stated context. They do not turn a broad guide into individualized advice or transfer rights to reproduce the original material.
United Kingdom home food garden editorial synthesis — version 1
Global Garden Planner
Original seven-profile model, planting bands and en-GB corpus. It remains an editorial draft until an independent UK agronomic review is recorded.
What is frost and ice?
Met Office
Supports distinguishing ground frost, air frost and current forecast uncertainty. It does not provide an operational sowing date.
UK regional climates
Met Office
Supports broad east–west, north–south, maritime and topographic context. The project profiles and month bands are original and are not a transformation of Met Office regions or data.