How is Greece in April?

Where in Greece- it will vary

We had good friends go to Santorini in late April. They had spring jackets on all the time but the weather was clear and beautiful.

Athens, Crete, Santorini, Thessaloniki.

Thanks for any help.
Just want to have enough warm and enough cool clothes.
I read that the average high temperature is 65-69 F.

Plan for 50-60s in Crete, warmer towards the end of the month. Cooler in Thessaloniki. To me that means pants and a light jacket, rain likely not much of an issue.

If you plan on being there the 25-29th of April, Easter may impact your plans, so take a look at that.

We were in Athens in early April 2018. A light jacket that offers some rain/wind protection was helpful, especially for mornings and evenings. We got some rain a couple of days.