Because of the mountainous geography of Crete as well as its location at the edge of the European continent it is very difficult to predict the weather accurately. You will often need to look at several different weather reports (which may not all agree with each other) in order to get an idea of what is probable. possible and less likely.
There are a number of weather reports for Crete. Here are the most useful ones:.
Meteo.gr offers a number of weather stations from this link showing you the current and past conditions in Crete. You can also see their forecasts for a number of places in Crete under the following links:
Poseidon.gr is another excellent source of weather information and includes sea conditions.
For a very detailed (and complex interface, not so good on mobile phones) see WeatherOnline