Basic Information on Oman Area : 309500 Square Kilometres Population : 4.345 million according to 2014 estimates Density of population : 8.8 per square kilometre. Capital : Muscat Official Language : Arabic language (English language spoken widely). Religion : Islam. Time : Four hours ahead of GMT Currency : RO.1 = US$ 2.6 ( 385.0 Biza = US $ 1) Weather : Hot and humid in summer and moderate in winter Measurements : Metric system Electricity : 220 Volt. Population Growth Average : 6.4% National Day : Falls on November 18th every year (two-day holiday later in the same month). Official holidays : The days vary according to the Hijrah year: Prophet's birthday - Al Isra'a W'al mira'ag - Eid Al Fitr - Eid Al Adha and the New Hijrah year. Official Working Hours : Sunday to Thursday 7:30 am to 2:30 pm with the exception of Ramadhan during which work starts at (9 am to 2 pm) Private sector`s official working hours from Sunday to Thursday ( according to companies system ).