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 Overnight temperatures are generally mild with an average low of 12.6 Â°C (54.7 Â°F). 2  In September the mean daily temperature range/ variation is 7.4 Â°C (13.3 Â°F). 3  The weather in September is somewhat dry with rain at times. 4  Just 75.5mm (3in) of liquid is released during an average of 10 days.