When the RTA introduced various season tickets that were valid on the Metro, Tram and Bus, the only ticket that could be bought without having to apply for a Blue Nol Card was the one day pass.
However, this has changed recently (as pointed out by one of our readers Alex) and this has not been updated accordingly on the RTA website (but has been confirmed with them).
You can now buy a weekly season ticket on either a Silver, Gold or Blue Nol card. This means that visitors to Dubai are now able to buy longer season tickets than one day if they wish to use the Metro more frequently and this would make it worthwhile for them.
You can see all of the ticket prices here but the cost of a weekly ticket in Silver class is 110 dirhams for all zones. This means that if you make 15 journeys (over 3 zones) or more in a week then it may well be worthwhile to get a weekly ticket.
The cost of the weekly pass for all zones in Gold Class is 220 dirhams.
Nol season tickets are valid for as many journeys as you wish to make in the period. You can buy the weekly tickets from any Metro station or service centre.