Direct answer
Expect hot, mostly sunny weather in Barcelona from July 31 to August 2, with daytime highs in the low-to-mid 30s °C (about 88–95°F), nights in the mid-to-high 20s °C (about 75–80°F), light coastal breezes and a low chance of isolated late-afternoon or evening showers.
Details & typical conditions
Practical tips
If you’d like, I can fetch a live 3-day forecast now — tell me if you want temperatures in °C or °F and whether to include hourly details.