Having the largest population among towns around the lake, Siófok is often referred to as the capital of the Lake Balaton. It is mostly famous for its huge nightlife and the never ending parties, especially during the weekends. The town is often called "the partying capital of Hungary". But it is important to know that outside the town centre, there are many quiet and peaceful beaches and strands for every age group. The party season usually begins by the start of the summer break at schools and the end of the spring term at universities which is the end of June, early July. The last party events are on the last weekend before the start of school in September.
From end of September to beginning of May, Siófok is a quiet little town, attracting conferences and wellness tourists. In the recent years, many Hungarian families have moved to Siófok from bigger towns looking for a peaceful life that it provides off season. Thus, the population in the last 10 years increased with 15%, which is quite unique in Hungary, where the population in general has been decreasing for decades.
Siófok is located on a fairly flat area at the south-east end of Balaton. As the north shore is quite hilly the wind usually hits the south coast bringing some random heavy storms usually in late June but other than that the climate is very hot all summer specially in August when the temperature can go up to as high as 35-38 degrees Celsius (95-100 degrees Fahrenheit). People who don't like too hot weather can travel to the lake in May or September when it is not that hot but warm enough to jump in the water or get tanned. Off main season, in April, May, and September, beach compatible temperatures are not unusual (20-25 degrees Celsius or 70s in Fahrenheit with a water temperature around 18-20 degrees Celsius or high 60s in Fahrenheit), but these months are rather unpredictable regarding weather. As you do not have to be afraid that you will not find any accommodation during that time of the year, it is worth to check the weather forecast a week or two before arrival and book accordingly.
Balaton, being a shallow lake, is warmed up by the Sun very quickly. At the end of July or in August, the water temperature can be as high as 24-26 degrees Celsius (75-79 degrees Fahrenheit)
Many tourists come to the city every summer (more and more every year). During the 20th century, the lake and Siófok was a popular destination for German tourists - in fact, most of the visitors were from Germany. Nowadays, about half of the tourists come from other Hungarian regions, and the other half from foreign countries. Most of the foreign visitors come from Germany, Netherlands, Austria, Italy, Poland and Slovakia, but the lake has seen many other nations as well.
There is a small international airport in Sármellék, near Héviz, called Héviz Balaton Airport (IATA: SOB) , which is about an hour drive from Siófok, with flights arriving from many European cities especially German cities like Berlin, Hamburg, Frankfurt, Düsseldorf, Erfurt, Leipzig, but also from Moscow and Riga. The Franz Liszt International Airport in Budapest  is just a 140 kilometers away, and is easily accessible using the M7 and M0 motorways.
Trains to Siófok leave from Déli pályaudvar and Keleti pályaudvar railway stations in Budapest, the journey taking about an hour and thirty minutes. Trains also run along the coast from Nagykanizsa in the west. There is a daily train between Venice and Budapest which stops at Siófok (and other cities like Ljubljana and Trieste).
Public transportation in Hungary is really cheap, a Budapest - Siófok journey costs about 2200 forints for an adult (USD 10 or about 7.5 Euros) in 2013, and students of the EU or Switzerland get 50% discount, and anyone under 26 years of age gets 33% discount from fares. This is valid for train and bus journeys as well.
There is no English language timetable available on the Internet for Hungarian bus lines, but there are regular busses between major cities in the Transdanube region and Siófok.
Most towns around the lake can be accessed by boat , the prices are relatively low, so it is worth to make daytrips during vacation to Siófok.
Siófok may not have a huge population, but in the summer it is capable of hosting hundreds of thousands of people. As most of the visitors are interested in the Lake Balaton, the city has a length of almost 15 kilometers. The most practical way of getting around is using a bicycle or a moped, both of which can be rented in Siófok for ~8 / ~15 Euros per day, respectively.
Since the town is rather long but quite narrow, the nearest beach is probably within a 5-15 minute walk. Also, when in the city center, walking can be the best choice for most, as parking can be hard during main season and relatively costly as well.
Siófok has a local bus system; the local transportation company charges ~1.5 Euros per trip. As the city has four train stops along the Budapest-Nagykanizsa railroad, it is very common to take the train from one end of the city to the city center or to the other end. It is probably the fastest way, although it takes quite a planning as trains stopping at each of the stations are a bit rare. However, train might be a good (and cheap) choice at the end of the party, as the first ones leave from the city center as early as 4 am.
Taxis have a flat rate which changes from summer to summer. 10-15 Euros per trip is general, regardless of the distance. During the night the price might double! Make sure that you agree in a price with the driver before you sit in the car to avoid getting ripped off by a 'visiting cab driver'.
Like most of the places with tourists, Siófok is suffering from some of the negative effects of it, as well. Violent crimes hardly ever happen in Siófok, but thieves come to town together with the tourists, so it is best to watch out for your belongings at all times. Don't leave your valuables in the car, unattended on the beach, or on the table in the restaurant. If you choose to rent a holiday apartment or a house, make sure you close all the windows and doors when you leave for the beach or for the bars, as break-ins are also not unheard of during main season. All in all, the situation is not bad, not worse than any other beach town in Europe, but common sense can save you a lot of money for sure.
Sándor Restaurant, Erkel Ferenc utca 30. . If someone feels like having a traditional Hungarian meal with friendly service then this is the place to go. The restaurant can be found just outside of the town centre. It offers party service as well and it has been voted into the top 100 restaurants in Hungary in 2002.
Mala Garden, Petőfi sétány 15./a . This place is a special design hotel and restaurant. On the menu you can find Hungarian specialities and Asian foods aswell. The whole building and the interieur has been inspired by the modern architecture of Bali Island.
Amigo Restaurant and Pizzeria, Fo Utca 99. Not a Mexican Restaurant despite the name. Open all year round - great pizzas from a wood fired pizza oven. Hungarian dishes too. Very reasonably priced. Service can, however, be rather slow. (46.9089724,18.0585565) edit
Traditional Hungarian food made by locals can be tasted if you come in August, when the Bogrács fesztivál (Cauldron festival) takes place. Several different types of goulash, Hungarian fish soup are just a few of the dishes you want to give a chance to.
Marcipán Café and Confectionary offers petit déjeuner, cakes, coffees at a reasonable price in the very heart of the city. Address here.
Café Móló, Szent István sétány 1. . Café Móló is one of the most popular bars in Siófok. It's not the cheapest place so it is mostly visited by people over the age of 25. There is a sandy beach right in front of the restaurant so you can enjoy the sunset whilst having a colourful cocktail.
Bacardi Music Café, Petőfi sétány 5. . During the day this terraced place is a cocktail bar and osteria. When the night begins they open the dancefloor in the back and it often ends up in great parties.