Abu Dhabi experiences a hot and arid climate. You can expect sunny skies all year round. So be aware and pack accordingly. Keep water with you at all times.
Summer: Between July and September, Abu Dhabi can be humid and hot with temperatures exceeding 100-degrees Fahrenheit or 45-degrees Celsius. Sandstorms also occur intermittently. In October, the temperature is very dry. Hence, making it just okay but not good for vacationing.
Winter: The best time to go Abu Dhabi is during the winter season from November to April. This is when the temperatures are cool and gives you the opportunity to enjoy desert safaris. Pack in warm clothes for these months, because it can get a little breezy. One can enjoy the Dubai shopping festival during this time as well.