Iceland may have a reputation for relatively mild winters, but this week is going to be positively Arctic. While the week to come may indicate both light winds and low precipitation, the temperature forecast is decidedly less merciful.
The Icelandic Met Office shows that temperatures will be around or well below -10°C for pretty much the entire country, until Sunday afternoon. At that time, temperatures will begin to creep above the freezing mark, in the south anyway; the rest of the country will remain solidly below zero.
Regionally, the lowest temperatures will of course be in the Highlands, where they will reach as low as -25°C, but you really have no business being there in the winter anyways.
In addition, an avalanche watch is still in effect in the Westfjords. The region, known for its steep mountainsides pushed right up against the sea, is also rife with avalanches of all sizes. Exercise caution if you engage in some winter hiking there.