Climate
As far as climate goes, the late-December to mid-April dry season is the most pleasant. But of course, this is when everyone else goes to Costa Rica, so prices increase and hotels are full. Although some roads are impassable in the wet season, it's still worthwhile to visit at this time, and things are much quieter.
April, May and mid-October to mid-December should give you the best of both worlds.

Festival Calendar
2nd week in March - San Antonio de Escazu (outside San Jose) hosts the annual Oxcart Driver’s day festival, featuring parades and open-air marimba night dancing
April - Holy Week/Easter - Almost as festive as Christmas with lots of parades and attractions.
May 1st - Battle of Rivas
July 25th - Guanacaste Day
August 2nd - Virgin of Los Angeles day
September 25th - Independence Day
October 12th- Columbus Day
December 18th – January 5th - (San Jose) - A great time to be in the capital. Fireworks displays, dancing, confetti throwing, horse parades, bull running, carnivals and fairs all celebrating Christmas

Currency
The Costa Rican Colon is the official currency and Costa Rica is one of the more expensive countries in Central America. For budgeting purposes, between 20 and 25 USD per day should be sufficient in San Jose. Meals are much cheaper in rural areas. While you may have little difficulties changing Australian dollars or British Pounds in San Jose, the US dollar is best for the smaller towns. The same can be said por travellers’ cheques and credit cards. Banks are generally open between 9am to 3pm, but the line-ups can be frustrating. You may find yourself in one line to get your transaction approved and then another line to actually receive your money. When changing travellers’ cheques, you will most likely be required to show your passport and even your proof of purchase, so keep your receipt with you. Remember to ask for smaller denominations as changing larger colones bills can be troublesome in rural areas. You can easily withdraw colones with your credit card, but not US currency

Visas
Visa requirements vary greatly from country to country. It is your responsibility to check with your local Costa Rica consulate for the most current requirements. At present, citizens of the USA, Canada, the UK, most Western European countries, Argentina, Israel, Japan, Panama, South Korea and Uruguay do not require a Visa for travel of up to 90 days. Citizens of Australia, New Zealand, Ireland, France, Sweden and most Eastern European countries do not require a Visa for travel of up to 30 days.

Health

Dengue fever, transmitted by the Aedes aegypti, is unlike the malaria mosquito, as it is most active during the day, and is found mainly in urban areas, in and around human dwellings. Signs and symptoms of dengue fever include a sudden onset of high fever, headache, joint and muscle pains, nausea and vomiting. A rash of small red spots sometimes appears three to four days after the onset of fever. Severe complications do sometimes occur. You should seek medical attention as soon as possible if you think you may be infected. A blood test can indicate the possibility of the fever. There is no specific treatment. Aspirin should be avoided, as it increases the risk of haemorrhaging. There is no vaccine against dengue fever.

Cholera (low risk) This diarrhoeal disease can cause rapid dehydration and death. Cholera is caused by a bacteria, Vibrio cholerae. It is transmitted from person to person by direct contact and often via healthy carriers of the disease or via contaminated food and water. It can be spread by seafood, including crustaceans and shellfish, which get infected via sewage. Cholera exists where standards of environmental and personal hygiene are low. Every so often there are massive epidemics, usually due to contaminated water in conditions where there is a breakdown of the normal infrastructure. The time between becoming infected and symptoms appearing is usually short, between one and five days. The diarrhoea starts suddenly, and pours out of you. It’s characteristically described as ‘ricewater’ diarrhoea because it is watery and flecked with white mucus. Vomiting and muscle cramps are usual, but fever is rare. In its most serious form, it causes a massive outpouring of fluid (up to 20L a day). This is the worst case scenario – only about one in 10 sufferers get this severe form. It’s a self-limiting illness, meaning that if you don’t succumb to dehydration, it will end in about a week without any treatment. You should seek medical help urgently; in the meantime, start re-hydration therapy with oral re-hydration salts. You may need antibiotic treatment with tetracycline, but fluid replacement is the single most important treatment strategy in cholera. Prevention is by taking basic food and water precautions, avoiding seafood and having scrupulous personal hygiene. The currently available vaccine is not thought worthwhile as it provides only limited protection for a short time.

Hepatitis - Several different viruses cause hepatitis and they differ in the way that they are transmitted. The symptoms in all forms of the illness include fever, chills, headache, fatigue, feelings of weakness and aches and pains, followed by loss of appetite, nausea, vomiting, abdominal pain, dark urine, light-coloured faeces, jaundiced (yellow) skin and yellowing of the whites of the eyes. Hepatitis A is transmitted by contaminated food and drinking water. Seek medical advice, but there is not much you can do apart from resting, drinking lots of fluids, eating lightly and avoiding fatty foods. Hepatitis E is transmitted in the same way as hepatitis A; it can be particularly serious in pregnant women. Hepatitis B is spread through contact with infected blood, blood products or body fluids, for example through sexual contact, unsterilised needles (and shaving equipment) and blood transfusions, or contact with blood via small breaks in the skin. The symptoms of hepatitis B may be more severe than type A and the disease can lead to long-term problems such as chronic liver damage, liver cancer or a long-term carrier state. Hepatitis C and D are spread in the same way as hepatitis B and can also lead to long-term complications. There are vaccines against hepatitis A and B, but there are currently no vaccines against the other types. Following the basic rules about food and water (hepatitis A and E) and avoiding risk situations (hepatitis B, C and D) are important preventative measures.