On 5-9-15 we got 9.75 inches of rain in less than 10 hours.  Over 5 inches came within 2 hours according to an acquaintances electronic rain gauge. There was not a drop of water or wet feeling inside the box. It has several of my electric and hand tools. All were dry.  This box was in the back of my pickup parked in the drive way.  A lot of the time the wind was blowing from the West and the pickup was parked outside on the East side of the garage.  Thus it was somewhat shielded - BUT not that much.  I didn't think the 1 latch would hold the lid tight enough but it did.  I have a larger box in a trailer and water got into it a few weeks ago.  There was only 1 of the 2 latches closed so that could be the reason.