The last third of the month saw northerly winds bring in air from the north pole. Minimum temperatures at night were only just above zero in central Belgium, with even a bit of frost a couple of nights ago.
Spring did not start yet, except for a couple days early April. The rest of the month was wet, and even included April showers bringing sleet and hail. However, this was not really exceptional: "April was rather cold, but the average temperature puts it only in around 40th place on the list of the coldest months since 1901", the VRT's weather presenter Frank Deboosere says.
There is good news though: spring is start at last in the coming days. We will gradually have more sun, and temperatures will gradually climb to reach 20 degrees Celsius in the second part of the week and next weekend.