Hardly any U.S. towns collect less precipitation than Opal: 8 inches a year
On a normal January night the air cools to about 5°. A year here swings 78° from midwinter lows to midsummer highs. Winter nights are cold: in January they are colder than in 98% of U.S. towns. If you like long walks, July and August offer highs of 81–83°.
A year in Opal at a glance
Each month’s typical high and low, and what it brings.
What stands out about Opal’s climate
Compared with towns across the U.S., with Opal’s place in Wyoming beside it.
What a year in Opal feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
A freeze is possible in every month
About 246 nights a year fall to 32° or below, and 44 to 0° or below. Frost and day counts come from NOAA’s station at Kemmerer 2n, WY, 11 miles from the town’s center, 270 ft higher.
The 2023 USDA map puts Opal’s center in zone 4b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −23°. 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 50 inches of snow a winter
Snow, measured at Kemmerer 2n, WY, falls mostly in January. Precipitation (rain plus melted snow) adds up to 8 inches a year; May is the wettest month and February the driest. Rain or snow falls on about 53 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Opal
99% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from September 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 Kemmerer 2n, WY.
Living with Opal’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
Zone 4b, and frost can come in any month. The longest frost-free stretch in half of years is about 66 days.
Months with highs of 62–84° and lows of 40° or more: July and August.
Parks & trails →Of the yearly building losses FEMA expects in Opal from natural hazards, avalanches are the largest share (83%); heat waves, cold waves, winter storms and ice storms together are 1%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Opal and similar climates
TownRatings has no climate map of the towns around Opal yet.
Climates most like Opal’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 |
|---|---|---|---|---|
| Opal, WY | 5° | 83° | 8" | 50" |
| Gunnison, CO | 0° | 82° | 12" | 50" |
| Williston, ND | 2° | 84° | 15" | 48" |
| Havre, MT | 6° | 85° | 13" | 41" |
| Taos, NM | 11° | 84° | 13" | 28" |
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 Opal averaged 1.6° warmer than the 1900s. The biggest change is in March (+3.7°).
A bigger shift than in 64% 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 Opal compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Opal’s place among Wyoming’s.
Opal weather by month
Highs, lows and precipitation from NOAA’s grid at Opal’s center; snow, wet days and snow on the ground from Kemmerer 2n, WY. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 30° | 5° | 0.5" | 11.6" | 5 | 8° – 26° |
| February | 32° | 7° | 0.4" | 9.6" | 4 | 11° – 31° |
| March | 43° | 18° | 0.6" | 6.1" | 4 | 23° – 37° |
| April | 52° | 24° | 0.8" | 3.0" | 4 | 31° – 43° |
| May | 63° | 33° | 1.4" | 1.4" | 6 | 43° – 52° |
| June | 74° | 40° | 0.9" | 0.1" | 4 | 51° – 62° |
| July | 83° | 46° | 0.5" | 0.0" | 3 | 55° – 69° |
| August | 81° | 44° | 0.8" | 0.0" | 4 | 58° – 65° |
| September | 71° | 36° | 0.9" | 0.4" | 4 | 50° – 57° |
| October | 57° | 26° | 0.8" | 1.8" | 4 | 33° – 48° |
| November | 41° | 15° | 0.5" | 6.2" | 5 | 17° – 34° |
| December | 30° | 5° | 0.5" | 9.5" | 6 | 12° – 26° |
| Year | 55° | 25° | 8.4" | 49.7" | 53 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 11° to 31°. August is the most reliable, staying within 7°.
Where Opal’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 Opal’s center.
- Snow: Kemmerer 2n, WY.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Kemmerer 2n, WY, 11 miles from the town’s center, 270 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 Opal’s climate
What is the weather like in Opal?
A typical July afternoon reaches 83°, a January night drops to 5°, and about 50 inches of snow falls in a normal winter. Colder January nights than 98% of U.S. towns; cooler July afternoons than 74% of U.S. towns.
How cold does it get in Opal in winter?
January nights average 5°. About 246 nights a year reach 32° or below and 44 reach 0° or below. In the coldest January of the last 30 years the month averaged 8°.
How much snow does Opal get?
About 50 inches in a normal winter at Kemmerer 2n, WY, most of it in January.
How hot does it get in Opal?
July, with a typical high of 83° and a low of 46°. About 4 days a year reach 90° (Kemmerer 2n, WY).
When is the first and last frost in Opal?
There is no reliable frost-free season: at Kemmerer 2n, WY, every month has nights at 32° or below, about 246 a year. In half of years the longest stretch without a freeze is about 66 days.
What growing zone is Opal in?
Zone 4b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −23°.
What is the best time of year to visit Opal?
By one simple rule (highs of 62–84° and lows of 40° or more), July and August. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Opal getting warmer?
Yes: 1991–2020 averaged 1.6° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 64% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Opal.
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.