Late spring and early autumn (May to June and September) bring the mildest, brightest weather and lighter crowds. August is the city's peak, when the Fringe and International Festival fill it with shows but also with visitors and higher prices, so book far ahead. Winter is cold, dark and often wet, but atmospheric, with Christmas markets and Hogmanay; expect rain and wind in any season.
Edinburgh's weather changes fast and can be cold, wet and windy even in summer, especially on exposed spots like the Castle, Calton Hill and Arthur's Seat. Carry a waterproof layer and check the forecast before a hill walk, as conditions at the top can differ sharply from the streets.
The city is built on hills, with steep cobbled streets, long staircases (closes) and uneven paving that are slippery when wet. Wear sturdy, grippy shoes, take care on Arthur's Seat's rocky paths, and use the many stepped shortcuts carefully rather than rushing.
Edinburgh is generally safe, but the usual big-city care applies around busy nightlife areas and during festival crowds. Keep an eye on your belongings in packed pubs and events, and use licensed taxis or booked cars rather than unlicensed lifts late at night.