In April you can climb the Acropolis without the glare and heat that, by July, send sensible Athenians indoors by lunchtime. Highs in Athens sit around 20°C and the sun is out for more than eleven hours a day, plenty of light for a full day on foot. If Orthodox Easter lands in the month, you also get the candlelit Resurrection night and a capital that goes quiet as residents drive off to their villages.
Book the Acropolis on hhticket.gr, the state's Hellenic Heritage site, and take the first slot of the morning or one late in the afternoon. The entry window is tight, roughly fifteen minutes either side of your slot, so skip the long breakfast in Plaka beforehand.
Steer clear of 18 April. It is International Monuments Day, when state-run sites across Greece open free, the Acropolis included. Long queues form at its gate from opening time.
For the view of the Parthenon, get off the rock. Cross Dionysiou Areopagitou and climb Filopappou Hill, on paths through pines and olives that the architect Dimitris Pikionis laid in the 1950s from marble, salvaged stone and broken pottery. The small church of Agios Dimitrios Loumbardiaris sits beside the way up. The old marble is polished smooth, so wear shoes that grip. Go an hour before sunset, while most visitors are still on the other hill.
Orthodox Easter often falls in April, sometimes in early May, and most years on a different Sunday from Western Easter, so don't assume the Easter on your own calendar is the one that counts here. On Holy Thursday and Good Friday a large share of the city drives off to family villages and the islands, and Piraeus, Rafina and Lavrio are packed with ferry passengers. Book island crossings and intercity buses early, or stay in town, which for once is quiet.
On Good Friday evening each parish carries its Epitaphios, a bier covered in fresh flowers, through the neighbourhood behind the priest, with everyone holding beeswax candles. Watch from Agios Georgios on the summit of Lycabettus, where the processions flicker across the city below before the church's own winds down the hill. Late on Saturday comes the Resurrection service: the lights go out, the flame passes from candle to candle at midnight, and bells ring while fireworks go off across the city. Any neighbourhood church will do. Afterwards people carry the flame home still lit and use it to smoke a small cross above the front door. Look up at the lintels as you walk about the next morning.