| Boulder Mountains | |
|---|---|
| Highest point | |
| Peak | Haystack Mountain | 
| Elevation | 8,819 ft (2,688 m) | 
| Coordinates | 46°08′29″N 112°19′35″W / 46.14139°N 112.32639°W | 
| Geography | |
| Country | United States | 
| State | Montana | 
| Parent range | Rocky Mountains | 
The Boulder Mountains are a mountain range running roughly north to south located west of Boulder between Helena and Butte in the U.S. state of Montana.[1] Parts of the range are in four different counties: Deer Lodge, Jefferson, Lewis and Clark, and Silver Bow.[1]
Haystack Mountain, which reaches 8,819 feet (2,688 m), is the tallest peak in the range.[2][3] The three other highest peaks are Jack Mountain at 8,752 feet (2,668 m), Bull Mountain at 8,609 feet (2,624 m), and Thunderbolt Mountain at 8,597 feet (2,620 m).[2] All four peaks are in Jefferson County.[2]
Climate
Rocker Peak, 8,455 ft (2,577 m),[4] is near Jack Mountain (Montana), the second highest peak in the Boulder Mountains.[5] There is a SNOTEL weather station near the summit of Rocker Peak at an elevation of 8,000 ft (2,438 m). Rocker Peak has a subalpine climate (Köppen Dfc), bordering on an Alpine climate (Köppen ET).
| Climate data for Rocker Peak, Montana, 1991–2020 normals, 1983-2020 extremes: 8000ft (2438m) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year | 
| Record high °F (°C) | 55 (13)  | 
53 (12)  | 
58 (14)  | 
66 (19)  | 
73 (23)  | 
81 (27)  | 
85 (29)  | 
85 (29)  | 
81 (27)  | 
72 (22)  | 
59 (15)  | 
48 (9)  | 
85 (29)  | 
| Mean maximum °F (°C) | 43.2 (6.2)  | 
43.4 (6.3)  | 
49.6 (9.8)  | 
56.5 (13.6)  | 
63.8 (17.7)  | 
71.4 (21.9)  | 
77.1 (25.1)  | 
76.2 (24.6)  | 
72.1 (22.3)  | 
62.1 (16.7)  | 
49.0 (9.4)  | 
40.7 (4.8)  | 
78.2 (25.7)  | 
| Mean daily maximum °F (°C) | 26.8 (−2.9)  | 
27.6 (−2.4)  | 
34.2 (1.2)  | 
39.6 (4.2)  | 
48.0 (8.9)  | 
55.8 (13.2)  | 
66.4 (19.1)  | 
65.4 (18.6)  | 
55.8 (13.2)  | 
42.4 (5.8)  | 
31.6 (−0.2)  | 
25.1 (−3.8)  | 
43.2 (6.2)  | 
| Daily mean °F (°C) | 20.2 (−6.6)  | 
19.8 (−6.8)  | 
25.5 (−3.6)  | 
30.5 (−0.8)  | 
38.8 (3.8)  | 
45.9 (7.7)  | 
54.9 (12.7)  | 
54.1 (12.3)  | 
46.1 (7.8)  | 
34.5 (1.4)  | 
24.9 (−3.9)  | 
18.9 (−7.3)  | 
34.5 (1.4)  | 
| Mean daily minimum °F (°C) | 13.6 (−10.2)  | 
12.2 (−11.0)  | 
16.8 (−8.4)  | 
21.4 (−5.9)  | 
29.6 (−1.3)  | 
36.0 (2.2)  | 
43.5 (6.4)  | 
42.9 (6.1)  | 
36.3 (2.4)  | 
26.7 (−2.9)  | 
18.2 (−7.7)  | 
12.6 (−10.8)  | 
25.8 (−3.4)  | 
| Mean minimum °F (°C) | −8.1 (−22.3)  | 
−8.8 (−22.7)  | 
−2.0 (−18.9)  | 
7.0 (−13.9)  | 
16.6 (−8.6)  | 
26.6 (−3.0)  | 
34.0 (1.1)  | 
32.2 (0.1)  | 
22.3 (−5.4)  | 
8.4 (−13.1)  | 
−1.2 (−18.4)  | 
−7.8 (−22.1)  | 
−19.7 (−28.7)  | 
| Record low °F (°C) | −30 (−34)  | 
−42 (−41)  | 
−24 (−31)  | 
−8 (−22)  | 
7 (−14)  | 
16 (−9)  | 
16 (−9)  | 
16 (−9)  | 
4 (−16)  | 
−11 (−24)  | 
−27 (−33)  | 
−39 (−39)  | 
−42 (−41)  | 
| Average precipitation inches (mm) | 2.07 (53)  | 
2.16 (55)  | 
2.58 (66)  | 
3.50 (89)  | 
3.58 (91)  | 
4.08 (104)  | 
1.72 (44)  | 
1.52 (39)  | 
1.80 (46)  | 
2.16 (55)  | 
2.24 (57)  | 
2.11 (54)  | 
29.52 (753)  | 
| Source 1: XMACIS2[6] | |||||||||||||
| Source 2: NOAA (Precipitation)[7] | |||||||||||||
See also
References
- 1 2 "Boulder Mountains". Geographic Names Information System. United States Geological Survey. October 27, 2000. Retrieved January 23, 2013.
 - 1 2 3 "Montana's Tallest Peaks by Mountain Range". Montana State Library. Retrieved January 23, 2013.
 - ↑ "Haystack Mountain". Geographic Names Information System. United States Geological Survey. November 28, 1980. Retrieved January 23, 2013.
 - ↑ "Rocker Peak". Peakery. Retrieved November 23, 2023.
 - ↑ "Montana's Tallest Peaks by Mountain Range". Montana.gov. Retrieved November 23, 2023.
 - ↑ "xmACIS2". National Oceanic and Atmospheric Administration. Retrieved November 23, 2023.
 - ↑ "Rocker Peak, Montana 1991-2020 Monthly Normals". Retrieved November 23, 2023.