As stated, the weather here can be excellent generally between the middle to the end of November until around the end of March to the middle of April.
There is a major problem with smog and you will see a distinct layer of pollution all year round. Right now it tends to be between 1000 - 3000 amsl. The visibility can be 10+ km if the winds are right and especially after a shamal or a down pour in the winter months.
If you intend to shoot after March then you will be risking the prospect of reduced visibility and a build up of humidity. There will be increased mist and fog for a short period and we then settle into a period of 3 - 8 km for around 6 months, in haze and with the temperatures climbing into the late 40's mid summer.
Dubai being as it is there is filming all year round. There are no real slack periods anymore as the level of construction and change dictates the amount of flying.
heli
dubai is a Dubai government owned company and takes around 80 - 90% of the filming and photo work in Dubai. They can help you through the process of getting permissions which can be confusing and difficult as there several departments to go through and it can take up to 2 weeks to get approvals, or in some cases longer. Also, booking can be tight with all operators so once again you will need to plan the shoot and book your slots, permissions, etc well in advance.
All of the pilots have an average of 12 - 20 years in Dubai and all are highly experienced film pilots. They can help you with mounts, cameras, etc as they have an excellent relationship with the local providers and are also in the process of having their own side and nose mounts based on site at their hangar at the airport. They are also the only operator in Dubai with their own helipad situated near the Emirates Towers.
Hope this helps!
