Packing a suitcase: what clothes should you bring?
If you plan to visit Holland in summer (June, July, August), you can expect a decent amount of sun and temperatures exceeding 20/25 degrees centigrade during the day. So pack shorts, T shirts, slippers and your bathing suit... The nights are still comfortable and usually not cold but you will still need something warmer, like a long-sleeved top or light jacket.
Spring and autumn
The temperature in spring and autumn (March, April, May and September, October, November) generally range between 10 and 20 degrees centigrade so you’ll mostly wear long trousers and a long-sleeved top or shirt. On a sunny day it can be pleasantly warm and sometimes Bermuda shorts or a skirt will do. So your needs may vary and you should come prepared.
During winter months (December, January, February) it is often quite cold. Temperatures often fall below freezing at night and during the day, it won’t get warmer than 10 degrees or remain below freezing. So bring warm clothes! Warm pullovers, trousers and a jacket and gloves, a shawl, hat and warm shoes for really cold days.
And finally: whatever season you choose to visit Holland, there may always be rain. A raincoat and boots can come in handy for a walk on the beach or in the forest.