April - May
The shoulder season will begin slowly in some locales. You will notice the attractions that closed during the winter begin to open in April, but some will not open until May. The weather begins to warm in April, becoming quite warm by May. The downside is that April showers are quite real in Croatia -- nearly the entire country will see some sort of rain in the month of April. As the south of the country transitions out of a rainy period, the central and northern parts of the country will begin a rainy season which will last until at least June. Highs in Istria will be in the low to mid-60s in April, and will rise to the mid-70s in May. Nighttime temperatures in Istria will fall into the 40s and low 50s in April, and the low and mid-50s by May. Zagreb and Osijek will warm into the 60s in the month of April and the low 70s by May; lows will be in the 40s and 50s for those months, respectively. The central coast will warm from mid-60s during the day and mid-40s at night in April to low 70s and mid-50s in May. Split will warm into the 70s by April and the 80s by May; morning lows will be in the low to mid-60s. Dubrovnik will see conditions in the 60s and 70s and lows in the 50s and low 60s.
Holidays and Festivals:
March-April - Easter and Easter Monday (Uskrs i uskrsni ponedjeljak). Many Croatians attend midnight mass and Sunday morning sunrise Mass. Families cook ham dinners and elaborate painted eggs (pisanice) are exchanged. National holiday in Croatia.
May 1 - International Workers` Day (Medunarodni praznik rada). Parades and speeches from politicians give way to picnics and concerts later in the day for Croatian workers and their families. National holiday in Croatia.
May 7 - Feast Day of St. Domnius (Sveti Duje), Split, de facto public holiday in this city.
April-May - Ascension (Uzašašce), one of the four `holy days` for Croatian Catholics. Forty days after Easter. You will see some sporadic business closures.
May-June - Pentecost and Whitmonday (Duhovi, Duhovski ponedjeljak), seventh Sunday and Monday after Easter, some sporadic business and attraction closures.
May-June - Corpus Christi (Tijelovo), ninth Thursday after Easter. Croatians typically attend Mass and then walk in a procession through the streets near their church. National holiday in Croatia.