If you fancy more sightseeing such as history etc, April, May, September and October are the best time of the year.
If you desire having a sun holiday, then the best time is between May and October.

High season:
June, July, August are the months of high season in Kusadasi.

What to put in your luggage:

For summer time, it is good enough to bring a couple t-shirts, shorts and a pair of flip-flop. But also don’t forget your bikinis and swimsuits.
For daily trips to historical places, you will need comfortable shoes and hat.

Passport and Visa regulations:

If you are an EU member, you are not required to get a visa.. For detailed information about visa requirements, visit http://www.turizm.net/turkey/tips/visa.html .

Travel Insurance:

In certain circumstances, it may make sense. Let’s have a look:
If you're covered by medical insurance at home, you may also be covered while you're traveling abroad.

Please check to be sure that you're covered in Turkey. Other sorts of insurance also cover medical expenses:
Personal accident/injury protection may be included in your car rental insurance or not.

If you've purchased a trip cancellation policy, you've probably got some medical protection. Read your policy carefully and know what's covered.

Electricity

Turkey operates on 220 volts, 50 Hz, with round-prong European-style plugs that fit into recessed wall sockets /points.

Map

You can provide a map from your travel agency or one of the bookshops.

Time

Kusadasi is at UTC + 2 and on summer at UTC+3 ( because of the DTS) , on Istanbul, Athens time zone.

Essential Information - Kusadasi