Frost Mountain is a summit located south of I-90 and Cle Elum. It is on the lee side of the Cascades meaning that it tends to be warmer and dryer in summer and colder and dryer in winter. One ideally would not want to hike up this mountain on a very hot summer day. The area is also prone to wildfires in late July and August so be aware before heading to this region. It is not a very popular mountain but is still an excellent destination for families and peakbaggers alike. The summit itself once held a fire lookout on it from the 1950's to the 1980's. One can still see the foundation of the lookout tower on the summit. It should be noted that the true summit is the lookout tower and the subpeak 0.1 miles is about 30 feet shorter. It is forested but does also have good views toward the east.
The true summit of Frost Mountain does give panoramic views of neighboring Quartz Mountain and Taneum Butte to the west, Ellensburg and the desert to the east and Mission Ridge, the Teanaway and the distant Stuart Range to the north. Depending on what route is taken, one can get some views on the way up as well. The views are very worthwhile and satisfying.
There are a number of routes to the summit of Frost Mountain. I approached Frost Mountain from the south and west pulling of on Forest Road 115 and parking by the gate. From there it was a 3 mile roundtrip hike with 500 feet of elevation gain to the summit of Frost Mountain on either gravel road or hiking trail. I recommend this way if one is trying to do Frost Mountain and Taneum Butte at the same time.
One can also approach Frost Mountain from the Forest Road 3100. This way is about 3 miles roundtrip and about 900 feet of elevation gain. The footing on the trail can be iffy in spots from the motorcycle traffic that is on this trail. Still this trail is easy hike for all family members and takes little effort.
If one is a little more ambitious one can also approach from the north. It is very doable in a day but it much long and has much more elevation gain than the other two ways. I would not suggest that way unless somehow 3100 washes out or one really needs the exercise and one solely wants Frost Mountain and not Taneum Butte.
Though this mountain can be climbed throughout much of the year, it is best that it is climbed in mid-October when the western larches are in peak. The summers in this region are very warm and very dry. If the temperature is forecasted to be over 90 in Ellensburg than skip this mountain for another day.