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.
1 Average September temperature: 15.7ÂºC / 60ÂºF. 2  Average September high (day): 19.4ÂºC / 67ÂºF. 3  Average September low (night): 9ÂºC / 48ÂºF. 4  Record high: 32.8ÂºC / 91ÂºF. 5  Record low: 0ÂºC / 32ÂºF. 6  Precipitation**: anticipate 10 days of rain in September and 13 days involving light showers.