There is an ideal temperature range that makes Lewisia pygmaea var. sierrae feel at home. Under these temperature conditions, it's unlikely that you’ll have any issues with cold or hot damage to the foliage, but changing leaf colors can absolutely be a sign that Lewisia pygmaea var. sierrae isn’t happy. Try to keep your Lewisia pygmaea var. sierrae well within its preferred range of 70-85℉(21-30℃), but don’t panic if the temperature creeps up past 85℉(30℃) during the day or down to 70℉(21℃) at night.

If your Lewisia pygmaea var. sierrae happens to be planted outside, then there’s not much you can do to try to move it indoors. However, you can certainly provide cover in ways that will help it survive any extreme temperatures that may arise unexpectedly. For instance, you can always use a few stakes and some cloth to put together a shade tent that will block out much of the sun’s intense heat from direct sunlight exposure. Similarly, Lewisia pygmaea var. sierrae can be protected from the extreme cold and especially chilly winds by building a small greenhouse around the plant, which will create a greenhouse effect and warm the plant up. This can be done using garden stakes and any sort of clear or translucent plastic you may have around; if you have greenhouse plastic such as polycarbonate laying around, this works perfectly. Remove the greenhouse once temperatures warm up to 40℉(10℃) at night.

Generally speaking, Lewisia pygmaea var. sierrae needs to stay within its preferred temperature range all year long. However, that doesn’t mean that care should stay the same all year long. During the warmest months of the year, Lewisia pygmaea var. sierrae will need a little extra shade and a bit more of a breeze to help it cope with the hottest days. On the other hand, it may need to be moved away from chilly windows and doors during the cooler months in climates where temperatures drop below 40℉(10℃) at any point in the year.

Keeping your Lewisia pygmaea var. sierrae at the right temperature can be fairly simple. Depending on where you grow it, Lewisia pygmaea var. sierrae can be fairly easy to accommodate. For indoor growing, you can easily move the plant to different locations within your indoor space that best meet its temperature requirements. Avoid placing it near air conditioning vents, heaters, doors that open frequently, or drafty windows. It is a little more difficult to control the temperature around your Lewisia pygmaea var. sierrae if it’s grown outside. Of course, if it’s planted in a pot, you can simply bring it indoors when the temperatures outside get too hot or too cold for Lewisia pygmaea var. sierrae, but otherwise, you may need to take different measures to protect it from extreme heat or cold that may damage it irreversibly. Try placing Lewisia pygmaea var. sierrae under cover to protect from both the harsh sun that can overheat it and any cold wind that could be potentially deadly for your plant.