The time zone is CET=GMT+1 (so, for instance: the same as in Germany and France, 1 hour ahead of Portugal).
The international dialing number for Poland is +48, area code for Warsaw is 22.
Weather in Warsaw in the middle of August is usually quite pleasant although not always predictable. Most of the time it should be sunny, dry, and warm (upper twenties Centigrade), but summer storms with heavy rains may occur.
Poland's electricity supply is 230 volts (50Hz), and typical (continental C & E) European outlets are in use. Plug converter can be purchased in larger electric stores.
Measurements, dates, numbers.
All measurements in Poland are based on SI (metric) sytem. We use Celsius scale for temperature, litres for volume, metres for distance, etc. Continental European clothes sizes are in use. For reference on clothes sizes you may check this site.
In Poland the standard for writing numbers is different from English/American one. Comma (,) separates the number and its decimal expansion. Dot (.) is used to mark every third order of magnitude (thousands, millions, ...). So, for instance "Populacja 132.000" means Population of one hundred thirty two thousand, while price 12,50 zł means twelve Polish złoty and fifty grosz (50/100). Also, we use "proper" names for orders of magnitiude, i.e., 10 to the power of 9 is milliard (not billion) and billion is 10 to the power of 12.
When writing dates in Polish we never put the day of month in between month number and year number. Therefore, 01/07/2010 in a Polish document is always the first of July, never the seventh of January.
Polish currency unit is called "złoty" (international code PLN, abbreviation zł.) and it is divided into 100 groszy (abbr. gr) (More information about banknotes and coins). Most shops and service points do not accept any other currency. You can change cash in banks, hotels and exchange offices marked "Kantor". The rates are always listed outside and may slightly vary between different exchange offices. Most of private exchange offices (Kantors) do not charge commission. Please do not accept exchange offers from strangers. Here you can find current exchange rates - these are average rates of National Bank of Poland - NBP. For street exchange rates (approximation) one may look at this site.
It is not advisable to purchase larger amounts of Polish currency outside of Poland, as exchange rates tend to be unfavourable. Much better idea is to bring small amount of cash in a major currency (EURO, USD, JPY) and exchange it in "Kantor" or use ATM.
Most restaurants, hotels, travel agencies and shops accept credit and debit cards. The most popular are Visa (also Visa Electron), Master Card (also Maestro and Eurocard) but many others are accepted, e.g., American Express, Diners Club, JCB. The use of contactless payments for small purchases is quite widespread in Warsaw.
Cash dispensers (ATMs) accept major cards and are ubiquitous in central Warsaw.