In the cities you can use ATM´s, most accept international cards. If you have trouble finding one, many gas stations and supermarkets have an ATM inside. Both Córdobas and American Dollars are used. Beware of high denominations, some Nicaraguans seem reluctant -or simply cannot- break anything bigger than a 20 Dollar bill. Damaged or stained bills are not accepted. Outside the cities it might prove difficult finding an ATM so if you go to off the beaten path destinations take this into account. Touristic places like Corn Island or San Juan del Sur have ATM´s.
Nicaragua has two seasons: The rainy (or green) season lasts from May to mid-November- that does not mean it is raining continuously but there can be some heavy rain for an hour or two, mostly in the late afternoon or at night. The dry season is November- April. The Caribbean side sees more rain than the Pacific side. The mountainous northern regions of Estelí, Matagalpa, Nueva Segovia, Madriz and Jinotega have a fresh climate.
Nicaragua is hot, so make sure to bring light clothing. Outside of the touristic beach towns, do not walk outside without a shirt on or on flip flops. Be aware that topless sunbathing may attract unwanted attention.
Citizens of the United States, Canada, Japan and most European countries only need a passport that is valid until at least 6 months after your stay in Nicaragua. You need to pay US$ 10 for a tourist visum at the airport. To check if more requirements appeal to you, You can find the actual exchange rate here
You can see the actual exchange rate at Banco central