Here are some real-time radiation measurements from a geiger counter about 15 miles due west of Tokyo, Japan.
The levels appear to be slightly elevated from normal values for the area. This measurement sensor is about 150 miles south-southwest of the Fukushima Daiichi plant.
Current weather conditions for Tokyo are found here: http://park18.wakwak.com/~weather/WDlive/wdlive_index.html
It looks like winds are right now from the south and around 15-20 mph. What isn’t wanted is winds from the north and thankfully the forecast for the next couple days appears to keep it that way.