Map from Google - Rhodes

In the eastern Aegean island of Rhodes, a short distance from the Turkish coast, the climate is Mediterranean, with mild, rainy winters and hot, sunny summers.
Here are the average temperatures.
Average temperatures - Rhodes
RhodesJanFebMarAprMayJunJulAugSepOctNovDec
RhodesJFMAMJJASOND
Min (°C)9910131620222320171310
Max (°C)151517202428313128242017
Min (°F)484850556168727368635550
Max (°F)595963687582888882756863

Rainfall amounts to 700 millimetres (27.5 inches) per year, and is concentrated from October to March; the rains often occur in the form of thunderstorms, and sometimes can be abundant. In summer, basically it never rains. Here is the average precipitation.
Average precipitation - Rhodes
RhodesJanFebMarAprMayJunJulAugSepOctNovDecYear
RhodesJFMAMJJASONDY
Prec. (mm)15012075251530076590145695
Prec. (in)5.94.7310.60.1000.32.63.55.727.4
Days1197320001561155

Winter, from December to mid-March, is mild: daytime temperatures hover about 15/17 °C (59/63 °F). The rains are quite frequent, but there are also sunny days. Sometimes it can get a little cold: lows can drop to about 3/5 °C (37/41 °F), and highs about 7/10 °C (45/50 °F). Wind can increase the feeling of cold. In the plains, substantially it never snows (sometimes you can see the snow falling, but it does not accumulate on the ground), while on the inland hills, reaching up to 1,200 metres (3,900 feet), sometimes it can snow.

Spring, from mid-March to May, is mild, and becomes progressively sunnier and with less rain.

Summer, from June to mid-September, is hot, quite humid and sunny. The Meltemi, the wind from the north-west, blows from mid-May, cooling the air, but with lower intensity than in the central islands of the Aegean Sea, such as Mykonos or Naxos. In addition, sometimes there are some periods of intense heat, with maximum temperatures about 35 °C (95 °F).

Autumn, from mid-September to November, is pleasantly warm at the beginning, and gradually becomes milder, and also rainier.

The amount of sunshine in Rhodes is great in summer, when clear skies prevail, is very good in spring, while in autumn and winter, sunny periods alternate with others characterized by clouds and rain.

Lindos, Rhodes

The sea is warm enough for swimming from June to October, and reaches 25 °C (77 °F) in August and September. In this eastern part of the Aegean Sea, the sea is a bit warmer than in the central part, because of the lighter wind.
Here are the average sea temperatures.
Sea temperature - Rhodes
RhodesJanFebMarAprMayJunJulAugSepOctNovDec
RhodesJFMAMJJASOND
Sea (°C)171616171923242525232018
Sea (°F)636161636673757777736864

When to go

The best time to go to Rhodes, for a beach holiday, goes from June to mid-September. In early June it can still get a little cool in the evening: for safety you can bring a sweatshirt.
In May, not only the sea is still a bit cold, but the air can be cool for sunbathing, at least on certain days.
To visit the ruins of ancient Greece or the Middle Ages, the best time is spring, ie April and May, because in summer it can be hot. You can also choose autumn, which however is more rainy.

Back to the Dodecanese.