Depends on congestion and signal strength. What sort of technology does the wireless use? 802.11* or another technology like sat or line of sight stuff? Generally radio waves stuff offers reasonable latency over short distances where as sat stuff is tediously laggy.
For example, if wireless is provided via an 802.11b/g/n router in the same building you'll get normal latency - my laptop is on the 'net via wireless and gets average pings of 60 (neocron) and 30 (quake 3/everything else)
Katanya Nowakoska - PPU
Natalya Nowakoska - Rifles
Ciara Nowakoska - HC
Malevolence - Researcher