A slow spring

Personally a slow start to spring is better than last years see-saw weather from warm to cold to hot to frost.
It can be frustrating to witness slow growth and the advance of the calendar with no appreciable warmth. But the plants will make up for lost time, day length is increasing and once the sun comes out the growth can be extremely rapid.

Use the time to prepare for this sudden spurt.
Covering bare soil with black plastic will help to warm the ground, avoid the growth of weeds, protect the soil from soaking rain or, with the last couple of days of relentless wind, stop dry top soil from blowing off.

Remove weeds that start flowering early, particularly chickweed, annual grass, bitter cress, and remove sprouting perennial weeds. This is easy whilst any planted crops are still small, but also easy to put off, a slight flush of weeds in early spring will turn to a rash of weed seeds in early summer, so get them young.

Delay direct planting of seed or potatoes until the soil is warm. They will not grow in cold soil and you may end up wasting time and seed. The sowing times on seed packets are a guide, use your own judgement to decide whether it is warm enough to sow.

If you do want to get going then plant in modules so that the plants are ready to go once the weather becomes suitable. If you have a greenhouse or polytunnel this is easy but even a cold frame will suit many hardier vegetable types.  Many seeds will grow in modules: beetroot, Swiss chard, celery, lettuce, brassicas, onions, peas, beans, and herbs.

Finally consider how to protect seedlings when they are planted from the vagaries of the weather. I don't use cloches, my vegetable patch is too exposed and they are too expensive for the amount of plants I grow. I do however use micromesh which I find to be extremely beneficial. It will cover a large area, is relatively easy to pin down and will allow moisture through, both rain and evaporation. It creates a microclimate, reducing wind stress and raising the temperature. Additionally it protects seedlings from pests and predators.