What are the reasons for different Worldwide release dates of a movie?

Andrew Cripps (former president of Paramount Pictures International and United International Pictures) wrote an Overview of International Film Markets and Theatrical Distribution:

Studios split the International market into three main areas:

• Europe
• Far East (including Australasia)
• Latin America

The Distribution Process:

Distributors will consider their strategies from (at least) four perspectives:

• Global: where will the film work?
• Regional: how will we make it work in (say) Europe?
• National: how should we release it in each country?
• Local: are there any particular local conditions that need to be taken into account within each country?

... the distributor will prepare a Territory Contribution Report identifying the revenue estimates for each market.

The views of senior studio bosses and regional and local managers will also be sought, with screenings held as early as possible to help build up a picture of the film's estimated International performance.

Campaigns for each title are planned well in advance, taking into account such factors as:

• US release dates
• Competitors' release schedules (information is generally shared between the majors to avoid clashes wherever possible)
• The distributors' annual budget and the rest of their slate for the year seasonal positioning (to take account of holiday periods, relevant awards ceremonies, other local factors)

The strategy and timing of the release will also take into account:

• censorship issues – when and how must the film be submitted for classification?
• translation for sub–titling and dubbing
• publicity screenings
• availability of key talent for promotional purposes
• availability of key media in each territory
• any promotional tie–ins and when the partners will be spending their money
• any additional local factors

Day and Date Distribution:

With the various exploitation windows closing, there is an increasing trend towards films being released internationally on the same day as (or close to) their North American release.

This has the advantages of

• reducing the opportunities for piracy
• enabling marketing campaigns from the US to roll over into other territories
• and allowing earlier exploitation of other windows.

On the other hand, day and date releasing requires new prints and means that marketing spend must be committed internationally before the studio knows how the film has played in the US.

It also reduces the time that the distributors have for sorting out dubbing, classification and other issues in each territory and makes it less likely that the talent will be available to promote it in as many markets.

All in all there is a lot to consider when distributing a movie internationally.

The reason for difference release date in different countries is because of following reasons -

1. Time it takes to prepare subtitles, dubs, to get the film through foreign ratings boards (and possibly re-cut based on that), to coordinate foreign marketing, and possibly to work around local movie schedules. For example in India movies only release on Friday but it differs from Us where movie can also release on other days too.

2. Then there's foreign distribution negotiations, which is an extremely complicated business. Sometimes movies have that locked down before they even shoot (because they're relying on that money); larger films may wait to prove themselves in domestic markets in order to get better deals overseas.

3. Finally, there's the physical difficulties in striking new prints (costly) or waiting for the old prints to finish up at home (takes a while) and then shipping them to the foreign markets. Print costs are is quite high and most movies can't afford to buy one for every theater in the world at the same time. Digital distribution should alleviate this problem somewhat in the next few decades.

All of these problems can be overcome--the largest of the blockbusters will sometimes have a simultaneous world-wide release date (which discourages piracy and allows you to take advantage of a single global marketing campaign), but I assume the vast majority of films don't have the money to take care of all of the issues before their release date.(source)

In the case of The Amazing Spider-Man Release dates outside the US were moved up to June in other countries to increase first-week sales.

Some other reasons also explained in similar question here 1,2.