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.
Throughout the month of September daytime temperatures will generally reach highs of around 23Â°C that's about 74Â°F. At night the average minimum temperature drops down to around 14Â°C, that's 57Â°F.In recent times the highest recorded temperature in September has been 35Â°C that's 95Â°F, with the lowest recorded temperature 5Â°C, about 42Â°F.e have created our own Swimming Water Temperature Index offering a guide to water temperature and comfort levels for swimming; In September, for the nearest coastal location, the temperature of the sea averages around 21Â°C, that's 70Â° Fahrenheit.