Photo: Jared Winkler · CC BY-SA 4.0Hartville reaches 100° on about 10 days a year, more than 91% of U.S. towns
January nights here settle around 15°. The gap between a January night and a July afternoon is 73°. It is a dry place: less rain and snow fall here than on 94% of U.S. towns. Plan time outside for June and September, when highs sit at 77–81°.
A year in Hartville at a glance
Each month’s typical high and low, and what it brings.
What stands out about Hartville’s climate
Compared with towns across the U.S., with Hartville’s place in Wyoming beside it.
What a year in Hartville feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 144 frost-free days a year
In half of years the last 32° night comes by May 11 and the first by October 3. Frost and day counts come from NOAA’s station at Guernsey Dam #2, WY, 3 miles from the town’s center, 390 ft lower.
The 2023 USDA map puts Hartville’s center in zone 5a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −18°. 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 28 inches of snow a winter
Snow, measured at Old Ft Laramie, WY, falls mostly in February and December. Precipitation (rain plus melted snow) adds up to 14 inches a year; May is the wettest month and January the driest. Rain or snow falls on about 70 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Hartville
90% 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 Guernsey Dam #2, WY.
Living with Hartville’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
144 frost-free days in zone 5a. The last frost comes by May 11 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 3.
Months with highs of 62–84° and lows of 40° or more: June and September.
Parks & trails →Of the yearly building losses FEMA expects in Hartville from natural hazards, river flooding is the largest share (42%); heat waves, cold waves, winter storms and ice storms together are 21%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Hartville and similar climates
TownRatings has no climate map of the towns around Hartville yet.
Climates most like Hartville’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 |
|---|---|---|---|---|
| Hartville, WY | 15° | 88° | 14" | 28" |
| Lockwood, MT | 15° | 88° | 15" | 35" |
| Stratmoor, CO | 18° | 88° | 16" | 33" |
| Chubbuck, ID | 17° | 88° | 12" | 39" |
| Gallup, NM | 17° | 88° | 10" | 34" |
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 Hartville averaged 1.6° warmer than the 1900s. The biggest change is in March (+3.6°).
A bigger shift than in 67% 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 Hartville compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Hartville’s place among Wyoming’s.
Hartville weather by month
Highs, lows and precipitation from NOAA’s grid at Hartville’s center; snow, wet days and snow on the ground from Old Ft Laramie, WY. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 40° | 15° | 0.3" | 2.2" | 4 | 5 | 22° – 35° |
| February | 42° | 16° | 0.5" | 6.3" | 5 | 5 | 18° – 37° |
| March | 52° | 23° | 0.9" | 3.1" | 5 | 3 | 27° – 46° |
| April | 59° | 30° | 1.8" | 3.5" | 7 | 2 | 38° – 51° |
| May | 68° | 40° | 2.6" | 0.6" | 10 | 0 | 47° – 59° |
| June | 81° | 49° | 2.1" | 0.0" | 8 | 0 | 59° – 70° |
| July | 88° | 56° | 1.6" | 0.0" | 7 | 0 | 66° – 76° |
| August | 86° | 53° | 1.2" | 0.0" | 6 | 0 | 65° – 74° |
| September | 77° | 44° | 1.1" | 0.0" | 6 | 0 | 55° – 65° |
| October | 63° | 31° | 1.1" | 2.4" | 6 | 1 | 38° – 52° |
| November | 49° | 21° | 0.5" | 3.2" | 4 | 3 | 23° – 44° |
| December | 40° | 15° | 0.4" | 6.2" | 4 | 6 | 19° – 32° |
| Year | 62° | 33° | 14.0" | 27.5" | 70 | 25 |
How much a month can swing
A normal is an average. November swings the most: from 1991 to 2020 its average ranged from 23° to 44°. August is the most reliable, staying within 9°.
Where Hartville’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 Hartville’s center.
- Snow: Old Ft Laramie, WY.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Guernsey Dam #2, WY, 3 miles from the town’s center, 390 ft lower; 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 Hartville’s climate
What is the weather like in Hartville?
A typical July afternoon reaches 88°, a January night drops to 15°, and about 28 inches of snow falls in a normal winter. Colder January nights than 86% of U.S. towns; hotter July afternoons than 66% of U.S. towns.
How cold does it get in Hartville in winter?
December nights average 15°. About 174 nights a year reach 32° or below and 13 reach 0° or below. In the coldest December of the last 30 years the month averaged 19°.
How much snow does Hartville get?
About 28 inches in a normal winter at Old Ft Laramie, WY, most of it in February and December, with snow on the ground about 25 days a year.
How hot does it get in Hartville?
July, with a typical high of 88° and a low of 56°. About 65 days a year reach 90° and 10 reach 100° (Guernsey Dam #2, WY).
When is the first and last frost in Hartville?
In half of years the last spring frost (32°) comes by May 11 and the first fall frost by October 3, about 144 frost-free days, at Guernsey Dam #2, WY.
What growing zone is Hartville in?
Zone 5a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −18°.
What is the best time of year to visit Hartville?
By one simple rule (highs of 62–84° and lows of 40° or more), June and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Hartville getting warmer?
Yes: 1991–2020 averaged 1.6° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 67% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Hartville.
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.