Volcanoes generate their own weather which can be severe and different from that only a few km away. Beware that some areas may be high risk areas for robbery etc. Look for evidence of recent ejecta. If you can see recent bombs on the ground then you can be hit. Limit your time in that area.
Recent bombs are black and stand out from the brown colour of older lava.
Falling rocks and unstable ground pose one of the most immediate hazards when climbing a volcano. If you can directly see the vent then the projectiles have a direct line of sight to you. Rocks and lava can be ejected at 200 m per second, sometimes even supersonic. You might be hit before you even hear the explosion. This may just lure you into a false sense of security and make you go closer than you would otherwise.