The Simple Answer :   The color of a star's visible light indicates its surface temperature: a relatively cool star glows red (longer wavelength), and very hot ones glow â¦ bluish-white or even blue (shorter wavelengths).
Over the course of the year, the temperature in Shetland typically varies from 37Â°F to 59Â°F and is rarely below 30Â°F or above 63Â°F. The warm season lasts for 82 days, from June 24 to September 14, with an average daily high temperature above 55Â°F. The hottest day of the year is August 6, with an average high of 59Â°F and low of 52Â°F. The cool season lasts for 133 days, from November 26 to April 8, with an average daily high temperature below 46Â°F.
As the month progresses, the cloud coverage increases, starting at 29% on September 1 st and increasing to 32% on September 11 th, 35% on September 21 st and 37% on September 30 th. The average sea temperature is very warm at 25Â°C, thanks to the waters retaining the heat from summer.t this time of the year, the average temperature starts off at 23-24Â°C at the beginning of the month and gradually drops until it reaches 20Â°C in the final few days. During September, the daily lows range slightly from 15Â°C to 18Â°C, dropping below 11Â°C or exceeding 22Â°C very rarely â only one day out of every ten.