Check-list

United States

Passport and visa service: See the Visa section on the Travel webpages on the US Department of State website
For further information: List and websites of U.S. Embassies, Consulates, and Diplomatic Missions
Contact your embassy

Current local time: It is %T:%M %A in New York, Washington DC, PhiladelphiaIt is %T:%M %A in Chicago, Houston, San Antonio, DallasIt is %T:%M %A in Los Angeles, San Diego
Summer time: From April to October.

Official language: English
Other languages spoken: Spanish, in particular in Arizona, Texas, California and New Mexico. Other languages, such as Amerindian languages (Navajo, Hopi, etc.) and also Chinese, Japanese, Italian, German, Polish, Greek, etc. depending on the community of immigrants.
Business language: English.
Getting some knowledge: English as a Second Language (ESL) program offered by Universities or private schools. Foreigners can take English classes at different levels and improve their writing and speaking skills in English.
Free translation tools: Cambridge Dictionaries - Online Dictionary
Systranbox - Free translation arabic-english-arabic
Lexilogo - Free dictionary arabic-english-arabic
Translated - Free translation arabic-english-arabic

Domestic currency: American Dollar
ISO Code: USD
To obtain domestic currency: It may be useful to arrive in the country with some dollars in your pocket. You may also change foreign currency into dollars at a bureau de change, use traveler’s checks or withdraw dollars directly from ATMs.
Possible means of payment: You can pay almost everything with your credit card. Another useful means of payment is the traveler's check because it is insured by the bank whereas cash is not.
Exchange rate on
Automatic Teller Machines (ATM): To find out the locations of ATMs in in the United States, click on the link to your credit card: Visa, Mastercard or American Express

Type of climate: Average Temperatures in Chicago: from -7°C in January to 20°C in June, in San Francisco from 12°C in January to 18°C in June and in New York from 0°C in January to 22°C in June.
For further information: US Department of Commerce: Climate Analysis Branch
National Weather Service
Federal Emergency Management Agency - Disaster Information

Telephone codes: To call in the United States from Tunisia, dial 00 (ou +) +1 (except Canada and the Caribbean)..
To call Tunisia from the United States, dial 011 (ou +) 216.
Mobile telephone standards: The US mainly uses Analog, TDMA, CDMA, GSM 1900. Also note that each standard may have multiple frequencies. Some phones can work in the US since the phone can support multiple GSM frequencies.
Another way to use a cell phone in the USA without subscription is to buy pre-paid cards.
Internet suffix: .us
Emergency numbers

Police, Medical, Fire	911 (112 from a cell phone)
Municipal Government	311