It is certainly a challenge to use a solar cooker in the winter months. As the sun moves closer to the southern horizon in the winter, solar cookers are naturally less effective. Because the sun is lower in the sky, it may require some adjusting or tilting of the reflector to capture the most sunlight. This adjustment allows the weaker sun rays to strike the entire surface of the jar.
Solar cookers naturally work better when the UV index is in the range 7 or greater. In the winter, cooking efficiency is diminished but can be accomplished through additional adjustment and increasing the cooking time. The solar “minimum” for the northern hemisphere occurs on winter solstice, about December 21st each year. The solar “maximum” occurs six months later, June 21st. Solar cooking works best from about March 20 – October 1 in the north. If you try to cook with the sun for the first time outside of this time window, do not be discouraged.
Couple of tricks that we’ve used during the winter months include, raising the jar a little higher up so the reflector does not need as much tilting or suspending the cooking vessel from a string within the reflector by using the holes punched in the wings of the reflector.
Please contact us if you have any questions – we’re happy to help! firstname.lastname@example.org or www.mysolarcooker.com
The Solar Zenith Team