Fort Steele · Photo: JERRYE & ROY KLOTZ MD · CC BY-SA 3.0Few U.S. towns get less rain and snow than Sinclair: 9 inches a year
Nights in January average 12°. Seasons differ by 73°, from the coldest nights to the warmest afternoons. Its January nights bite harder than in 91% of U.S. towns. Keep the boiler serviced for the months from October to April, which average under 50°.
A year in Sinclair at a glance
Each month’s typical high and low, and what it brings.
What stands out about Sinclair’s climate
Compared with towns across the U.S., with Sinclair’s place in Wyoming beside it.
What a year in Sinclair feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 105 frost-free days a year
In half of years the last 32° night comes by June 1 and the first by September 15. Frost and day counts come from NOAA’s station at Rawlins Muni Airport, 5 miles from the town’s center, 150 ft higher.
The 2023 USDA map puts Sinclair’s center in zone 5a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −20°. 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 9 inches of rain a year
May is the wettest month and December the driest.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Sinclair
97% 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 Rawlins Muni Airport.
Living with Sinclair’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
105 frost-free days in zone 5a. The last frost comes by Jun 1 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 15.
Months with highs of 62–84° and lows of 40° or more: June, August and September.
Parks & trails →Of the yearly building losses FEMA expects in Sinclair from natural hazards, avalanches are the largest share (52%); heat waves, cold waves, winter storms and ice storms together are 9%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Sinclair and similar climates
TownRatings has no climate map of the towns around Sinclair yet.
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 Sinclair averaged 1.7° warmer than the 1900s. The biggest change is in March (+4.1°).
A bigger shift than in 72% 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 Sinclair compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Sinclair’s place among Wyoming’s.
Sinclair weather by month
Highs, lows and precipitation from NOAA’s grid at Sinclair’s center. 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 32° | 12° | 0.4" | 13° – 30° |
| February | 35° | 14° | 0.4" | 18° – 31° |
| March | 46° | 22° | 0.6" | 26° – 41° |
| April | 55° | 28° | 1.2" | 35° – 48° |
| May | 65° | 36° | 1.5" | 44° – 55° |
| June | 77° | 44° | 0.9" | 54° – 66° |
| July | 85° | 51° | 0.8" | 61° – 72° |
| August | 83° | 49° | 0.7" | 62° – 70° |
| September | 73° | 41° | 0.9" | 53° – 61° |
| October | 58° | 30° | 0.8" | 36° – 51° |
| November | 43° | 21° | 0.5" | 19° – 40° |
| December | 33° | 12° | 0.4" | 16° – 27° |
| Year | 57° | 30° | 8.9" |
How much a month can swing
A normal is an average. November swings the most: from 1991 to 2020 its average ranged from 19° to 40°. August is the most reliable, staying within 8°.
Where Sinclair’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 Sinclair’s center.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Rawlins Muni Airport, 5 miles from the town’s center, 150 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 Sinclair’s climate
What is the weather like in Sinclair?
A typical July afternoon reaches 85°, a January night drops to 12°. Colder January nights than 91% of U.S. towns; hotter July afternoons than 51% of U.S. towns.
How cold does it get in Sinclair in winter?
January nights average 12°. About 192 nights a year reach 32° or below and 15 reach 0° or below. In the coldest January of the last 30 years the month averaged 13°.
How hot does it get in Sinclair?
July, with a typical high of 85° and a low of 51°. About 15 days a year reach 90° (Rawlins Muni Airport).
When is the first and last frost in Sinclair?
In half of years the last spring frost (32°) comes by June 1 and the first fall frost by September 15, about 105 frost-free days, at Rawlins Muni Airport.
What growing zone is Sinclair in?
Zone 5a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −20°.
What is the best time of year to visit Sinclair?
By one simple rule (highs of 62–84° and lows of 40° or more), June, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Sinclair getting warmer?
Yes: 1991–2020 averaged 1.7° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 72% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Sinclair.
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.