Photo: Bobak Ha'Eri · CC BY 3.0Hanna gets about 93 inches of snow a winter, more than 97% of U.S. towns
Peak summer warmth arrives in July, with afternoons near 83°. It is a dry place: less rain and snow fall here than on 96% of U.S. towns. Compared with 1901–2000, the average now sits 1.8° higher. The frost-free window for a garden runs roughly May 28 to September 13.
A year in Hanna at a glance
Each month’s typical high and low, and what it brings.
What stands out about Hanna’s climate
Compared with towns across the U.S., with Hanna’s place in Wyoming beside it.
What a year in Hanna feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 108 frost-free days a year
In half of years the last 32° night comes by May 28 and the first by September 13. Frost and day counts come from NOAA’s station at Elk Mtn, WY, 15 miles from the town’s center, 410 ft higher.
The 2023 USDA map puts Hanna’s center in zone 4b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −21°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 93 inches of snow a winter
Snow, measured at Elk Mtn, WY, falls mostly in April. Precipitation (rain plus melted snow) adds up to 12 inches a year; May is the wettest month and January the driest. Rain or snow falls on about 64 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Hanna
98% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through May.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Elk Mtn, WY.
Living with Hanna’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
108 frost-free days in zone 4b. The last frost comes by May 28 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Sep 13.
Months with highs of 62–84° and lows of 40° or more: June, July and August. 1.6 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Hanna from natural hazards, avalanches are the largest share (53%); heat waves, cold waves, winter storms and ice storms together are 7%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Hanna and similar climates
TownRatings has no climate map of the towns around Hanna yet.
Climates most like Hanna’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Hanna, WY | 13° | 83° | 12" | 93" |
| Belgrade, MT | 13° | 85° | 14" | 91" |
| Hailey, ID | 10° | 84° | 14" | 102" |
| Flagstaff, AZ | 16° | 84° | 18" | 90" |
| Durango, CO | 12° | 86° | 18" | 64" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Hanna averaged 1.8° warmer than the 1900s. The biggest change is in March (+4.3°).
A bigger shift than in 82% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Hanna compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Hanna’s place among Wyoming’s.
Hanna weather by month
Highs, lows and precipitation from NOAA’s grid at Hanna’s center; snow, wet days and snow on the ground from Elk Mtn, WY. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 33° | 13° | 0.6" | 9.0" | 5 | 15° – 30° |
| February | 35° | 14° | 0.7" | 15.1" | 5 | 18° – 30° |
| March | 45° | 22° | 0.9" | 13.2" | 6 | 26° – 40° |
| April | 53° | 28° | 1.4" | 17.0" | 8 | 34° – 46° |
| May | 63° | 36° | 1.8" | 5.1" | 7 | 44° – 54° |
| June | 75° | 44° | 1.2" | 0.0" | 4 | 54° – 64° |
| July | 83° | 51° | 1.0" | 0.0" | 4 | 61° – 71° |
| August | 81° | 49° | 0.8" | 0.0" | 4 | 60° – 68° |
| September | 71° | 40° | 1.1" | 0.4" | 4 | 51° – 60° |
| October | 57° | 30° | 1.2" | 11.6" | 5 | 36° – 51° |
| November | 43° | 21° | 0.8" | 9.4" | 5 | 20° – 39° |
| December | 33° | 13° | 0.7" | 12.5" | 6 | 17° – 28° |
| Year | 56° | 30° | 12.0" | 93.3" | 64 |
How much a month can swing
A normal is an average. November swings the most: from 1991 to 2020 its average ranged from 20° to 39°. August is the most reliable, staying within 8°.
Where Hanna’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Hanna’s center.
- Snow: Elk Mtn, WY.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Elk Mtn, WY, 15 miles from the town’s center, 410 ft higher; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Hanna’s climate
What is the weather like in Hanna?
A typical July afternoon reaches 83°, a January night drops to 13°, and about 93 inches of snow falls in a normal winter. Colder January nights than 89% of U.S. towns; cooler July afternoons than 69% of U.S. towns.
How cold does it get in Hanna in winter?
January nights average 13°. About 198 nights a year reach 32° or below and 13 reach 0° or below. In the coldest January of the last 30 years the month averaged 15°.
How much snow does Hanna get?
About 93 inches in a normal winter at Elk Mtn, WY, most of it in April.
How hot does it get in Hanna?
July, with a typical high of 83° and a low of 51°. About 3 days a year reach 90° (Elk Mtn, WY).
When is the first and last frost in Hanna?
In half of years the last spring frost (32°) comes by May 28 and the first fall frost by September 13, about 108 frost-free days, at Elk Mtn, WY.
What growing zone is Hanna in?
Zone 4b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −21°.
What is the best time of year to visit Hanna?
By one simple rule (highs of 62–84° and lows of 40° or more), June, July and August. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Hanna getting warmer?
Yes: 1991–2020 averaged 1.8° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 82% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Hanna.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.