Late spring (May and June) and early autumn (September and October) bring warm, mostly dry days ideal for walking the old town, with September a particular sweet spot after the summer crowds. Summer is lively and hosts the Sarajevo Film Festival in August, while winter is cold and snowy with skiing on the nearby Olympic mountains, though a valley inversion can trap air pollution on still days.
Sarajevo is a generally safe and relaxed city, but normal caution applies in the busiest parts of Baščaršija and on packed trams, where pickpocketing is the main petty risk. Keep bags zipped and valuables secure in crowds.
On cold, still winter days a temperature inversion can trap smog in the valley, and air quality can drop sharply. If you have respiratory issues, check air-quality readings and limit strenuous outdoor time on the worst days.
Left-over landmines from the 1990s war remain a risk in some rural and mountain areas outside the city, though not in Sarajevo itself. Stick to paved paths and marked trails in the countryside, and never wander into uncleared land.