Many people think the Bitterroot Valley has the best weather in Montana.
Known as the Banana Belt, the pleasant summers and mild winters make it a favorite for year-round living.
This article provides an overview of the weather in the Bitterroot Valley.
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Bitterroot Valley Weather Overview
The Bitterroot Valley is known for ideal summer weather with highs in the 80’s and lows in the 50’s.
Spring and fall both feature mild weather, with 50-70 degree days and 30-40 degree nights.
Bitterroot River and Bitterroot Mountains / Bitterroot Info
Winter brings cold temperatures and snow from November to March, with 30 degree highs and 15 degree lows.
While the Bitterroot Valley is known for mild year-round weather, winter weather can be severe, and summer temps are occasionally extreme.
Bitterroot Valley Average Monthly Temperatures (F)
Here’s the average daily temperatures for each month of the year in Hamilton, MT.
| HIGH | LOW | |
|---|---|---|
| January | 31 | 19 |
| February | 37 | 22 |
| March | 46 | 27 |
| April | 56 | 33 |
| May | 64 | 40 |
| June | 72 | 46 |
| July | 82 | 51 |
| August | 81 | 49 |
| September | 70 | 42 |
| October | 55 | 34 |
| November | 40 | 26 |
| December | 31 | 19 |
The Banana Belt of Montana
The Bitterroot Valley is known as the Banana Belt of Montana as the weather is far less severe than in other parts of the state.
The valley is sheltered by the Bitterroot and Sapphire mountains, blocking cold winds common throughout Montana during the winter months.
Double Rainbows in the Bitterroot Valley / Bitterroot Info
Spring comes early in the Bitterroot, with the first quality fly fishing of the year found on the Bitterroot River.
And fall days can be spectacular into November, with some of the most pleasant weather all year.
Bitterroot Valley Weather Details
Here’s a few interesting weather details for the Bitterroot Valley.
| Rainfall | 12 -15 inches per year |
| Snowfall at Lost Trail Ski Area | 200+ inches per year |
| Snowfall on Valley Floor | 18 – 24 inches per year |
| Sunny Days | 270 days per year |
| Growing Days | 130 – 150 days per year |
| Longest Day – June 21 | 15.8 hours of daylight |
| Shortest Day – December 21 | 8.6 hours of daylight |
| Altitude | 3,200 – 3,890 feet |
Bitterroot Valley Weather Random Info
Although generally pleasant, Bitterroot Valley weather can change quickly.
Plan accordingly with lots of layers — we always recommend taking along a jacket or coat whenever you are outdoors in Montana.
Nights are cool throughout the year, creating comfortable sleeping conditions.
Temperatures occasionally reach 100 degrees from late July through August, and sub-zero temperatures are possible from late November through February.
Bitterroot River Flooding its Banks in May / Bitterroot Info
Microclimates are found throughout the valley due to different elevations and bodies of water, resulting in wide temperature variations throughout the area.
The valley floor generally receives only a foot or two of snow each year.
The foothill locations throughout the valley can receive several feet of snow each winter.
The Lost Trail Ski Area commonly receives in excess of 200”.
That’s a Good Question
July is the warmest month in the Bitterroot Valley with average high temperatures around 82 degrees.
December and January are the coldest months in the Bitterroot Valley with average high temperatures around 31 degrees.
Stevensville, MT recorded 107 degrees on July 23, 2003
Hamilton, MT recorded -39 degrees on February 4, 1899
Additional Resources
This page provides more detailed information about the weather in Hamilton, MT