Here are two other ways to check if your body is dehydrated. Try this skin test. First, use two fingers to grab a roll of skin on the back of your hand (between where your watch sits and where your fingers start), advises Higgins. Pull the skin up about Â½ to one centimeter high and then let the skin go.
October is our wettest month, and Iceland gets an average low of 37Â°F (about 3Â°C) and highs of 45Â°F (7Â°C). Expect lots of rain, usually drizzle. The average amount of rain is 4 to 5 inches, or 101-127 mm. But as always, the rain amount depends on which part of Iceland you are visiting.
I always say that 15 August is the start of autumn in south-west Iceland, and certainly a few leaves do begin dropping around that date. But, in recent years we have also had warm weather in late August and into September. Night-time temperatures will depend very much on where you are, and how the weather behaves. Assuming that you are not in the interior (higher elevations, and therefore colder) in my opinion you should expect minima in the range 4-10Â°C in the south and 0-8Â°C in the north.