If during the day the temperature gets anywhere from 40 to 45 and at night it gets down into 26 to 30 should there be cover. They went from a break green to a dull green and a little bit of red / rust color
Thank you for the question. Our University publication covers your question. Here is the link to it: https://www.extension.umn.edu/garden/yard-garden/fruit/strawberries-for-the-home-garden/
Your berries are getting close to needing cover. It sounds like the leaves have had a touch of frost so far. I'm copying the paragraph from our publication that answers your question:
June-bearing strawberry plants continue to grow and produce runners until the frost kills the leaves. Keep removing runner plants if there is a lot of crowding.
After the plants have entered dormancy due to cold temperatures, and the temperatures are staying below 40°F, straw mulch should be applied about 4 to 6 inches over the top of the plants. This mulch will protect the plants from extreme winter cold so they will emerge again next spring. Remember, most day neutral cultivars are not quite hardy enough to over-winter in Minnesota, but it may be worth a try. Cover these with straw just as you would June-bearing cultivars.
Thank you for contacting Extension.