Yes, the warmer the temperature, the brighter the glow stick will glow. The heat will also shorten the chemical reaction time, which is of course the length of time that the light stick glows for. If it is colder, the glow stick will be dimmer and the reaction time will be longer, meaning that it will glow longer. Here is a tip to get an extra half hour out of your glow light stick: To reactivate a “dead” glow light stick or glow light product you just put it into boiling water for about 30 seconds and it will glow again for up to half an hour.