It can get a bit cold and very windy in Spring. It will usually be around 5degC in Spring, so do bring some warm clothings as well. It can get very very windy too, hence a wind breaker would be ideal.
Sometimes the temperature in Spring can get to 15degC with bright, warm sunshine. So do bring a not so thick jacket. Wear layers of clothes instead of one thick layer, cos you will be able to remove as it gets hot during the day, and wear more layers during the cold nights.