April in Portugal is mild and offers lovely days for sightseeing and exploring the outdoors. Pack a waterproof coat because it might get a bit rainy. Explore the cities but also enjoy some day trips.
Weather
The weather is one of the reasons Portugal is very popular among travelers. It’s always sunny here and, as a result, traveling is a lovely experience year round. April falls in spring and it’s a mild month. It can be quite rainy in the north and central regions, though. If you are looking to explore the outdoors and visit the sites, April is a lovely choice.
Sample temperatures:
Faro avg 19C / avg low 11C
Lisbon avg high 18C / avg low 10C
Porto avg high 16C / avg low 8C
>>read more about Weather in Portugal
Flights and accommodation
Unless you plan to visit Portugal during Easter (which falls on April 8 in 2012), you shouldn’t worry about booking the airfare and accommodation too far in advance. Hostels can be excellent choices if you are on a low budget.
With so many lost cost carriers serving Portugal, it’s a matter of finding the best offer for the time you plan to fly. Remember that typically, 4 to 8 weeks before departure the airfare tends to be cheaper.
What to do
IndieLisboa takes place in April and it’s an independent Portuguese film festival becoming more famous each year. But, of course, you need to speak Portuguese to be able to enjoy it.
Lisboa International Triathlon takes place in late April and you can definitely sit by the side and cheer the competitor. Or be inspired to take up sports yourself.
Lisbon Golf Coast Festival stars in early April and many golf clubs join in the fun and games. Maybe you’ve just discovered another passion.
Also, Liberty Day (April 25) is one of the holidays to keep in mind when planning the vacation in Portugal.
You should plan to do some Port tasting while you are here. Some other things to do in Porto include visiting the museums, sightseeing and enjoying the local cuisine.
While in Lisbon, plan to visit Belem , a historically important district in the capital. Other things to do in Lisbon include the museums, the monuments, a ride on Tram 28 – the iconic tourist tram – and see the city from above. And let’s not forget about the food and drinks in Lisbon either.
Put on the list the beautiful town of Sintra with its Moorish castle , located a short drive from Lisbon. And while you are here, you might want to check out the Palacio da Pena as well. It was built on the site of an old monastery and can be visited.
Buenos Aires is a desirable destination for any traveler. It has tons to offer travelers, with its unique mix of South American and European cultures. The people, the food, the wine, and the sites are all appealing and keep tourists coming back for more. The city is a great place to visit for a vacation, but what about 
Croatia and 
Unfortunately, although there were rumors about a direct ferry connection between Croatia and Greece, nothing has been done and you’ll have to connect through Italy. 
An easy way to travel between Croatia and Greece by train is to connect via Budapest (Hungary) and Bucharest (Romania). 
May is one of the best months to visit Croatia. The sunny and warm weather allows visitors to explore the coastal towns and islands but the mass of tourists haven’t arrived yet so there’s some laid back feel still present. But the café life is in full swing and the day trips organized by travel agencies start to be available.