The best time to visit the UAE is from October up until May.
In October the weather may still be quite hot (up to 35C), blue skies are the norm and the evenings are warm. At this stage the tourist season is well under way.
Daytime temperatures are ideal during November, December, January and February (around 24C) although the evenings may be a little cool (13C). North-westerly winds (shamal) sometimes blow during these winter months, bringing choppy seas. Most of the annual rainfall occurs between December and March, but this tends to be in the form of short heavy downpours that rapidly clear away. Indeed some winters are totally dry.
By March–April, temperatures are beginning to rise during the day (early 30s) but humidity is still low and the evenings are warm. May can be quite hot again (late-30s).
June–September are to be avoided, especially the July–August period which is very hot (high 40s) and humid (100 per cent). However hotels and golf clubs and other facilities offer very good deals during the summer months and it is worth remembering that hotels, shops, in fact all buildings, cars, buses etc are air-conditioned.