Climate snapshot for alpacas
98/100Alpaca climate comfort score
80°FAverage high, Jul
16°FAverage low, Feb
~2Days above 90°F (32°C) per year
~194Frost nights per year
20 inAnnual precipitation
1Barber pole worm months
17Hay bales / alpaca / year
Advantages
- Summers rarely reach heat-stress levels for alpacas
- Winters are cold but rarely severe
- Short or no barber pole worm transmission season
- Low meningeal worm risk
Overall rating: 98/100 — Excellent on our alpaca climate comfort score. Climate type: Warm-summer humid continental (Köppen Dfb).
Month-by-month climate
Average highAverage lowPrecipitation
| Month | High | Low | Precip. | Heat-stress index | Notes |
|---|---|---|---|---|---|
| Jan | 35°F | 17°F | 0.9 in | 95 · ok | frost |
| Feb | 37°F | 16°F | 1.0 in | 104 · ok | frost |
| Mar | 45°F | 22°F | 1.4 in | 106 · ok | frost |
| Apr | 51°F | 28°F | 2.2 in | 103 · ok | frost |
| May | 61°F | 37°F | 3.1 in | 117 · ok | grass |
| Jun | 70°F | 44°F | 2.8 in | 122 · ok | worms, grass |
| Jul | 80°F | 50°F | 1.6 in | 121 · caution | grass |
| Aug | 79°F | 49°F | 1.3 in | 127 · caution | grass |
| Sep | 69°F | 41°F | 1.5 in | 116 · ok | grass |
| Oct | 54°F | 32°F | 1.7 in | 98 · ok | frost |
| Nov | 42°F | 23°F | 1.2 in | 103 · ok | frost |
| Dec | 34°F | 16°F | 1.0 in | 88 · ok | frost |
Heat-stress index = average high (°F) + mean humidity (%). “Worms” marks months that suit barber pole worm transmission; “grass” marks the grazing season; “frost” marks months with average lows below freezing. Source: NOAA nClimDiv 1991–2020 county normals.
Alpaca care calendar for Sweet Grass County, Montana
January 35° / 17°F
- Freezing nights: keep water open and feed extra hay during cold snaps.
- Vitamin D for crias and juveniles (ask your vet about product and dose).
- Toenail check and trim.
February 37° / 16°F
- Freezing nights: keep water open and feed extra hay during cold snaps.
- Vitamin D for crias and juveniles (ask your vet about product and dose).
March 45° / 22°F
- Freezing nights: keep water open and feed extra hay during cold snaps.
- Vitamin D for crias and juveniles (ask your vet about product and dose).
- Toenail check and trim.
April 51° / 28°F
- Book your shearer now — spring calendars fill up fast.
- CDT boosters for females due next month; prepare a clean birthing paddock and birthing kit.
- Freezing nights: keep water open and feed extra hay during cold snaps.
May 61° / 37°F
- Run pre-season fecal egg counts so you know each animal's baseline.
- Cria season: check due dates daily, ensure crias nurse within 4 hours, dip navels and weigh crias daily for two weeks.
- Spring grass: switch from hay to pasture gradually over 1–2 weeks and monitor body condition.
- Toenail check and trim.
June 70° / 44°F
- Shearing month: shear the whole herd, and trim toenails, check teeth and body condition while animals are restrained.
- Barber pole worm season: fecal egg counts every 4–6 weeks, check eyelid color, pick up dung piles twice a week.
- Cria season: check due dates daily, ensure crias nurse within 4 hours, dip navels and weigh crias daily for two weeks.
- Breeding window for next year's crias (rebreed females 2–4 weeks after birthing).
July 80° / 50°F
- Warm spells possible — watch for open-mouth breathing in heavy-fleeced or dark animals.
- Cria season: check due dates daily, ensure crias nurse within 4 hours, dip navels and weigh crias daily for two weeks.
- Breeding window for next year's crias (rebreed females 2–4 weeks after birthing).
- Fly season: clean dung piles regularly and use traps around the barn.
- Toenail check and trim.
August 79° / 49°F
- Warm spells possible — watch for open-mouth breathing in heavy-fleeced or dark animals.
- Cria season: check due dates daily, ensure crias nurse within 4 hours, dip navels and weigh crias daily for two weeks.
- Breeding window for next year's crias (rebreed females 2–4 weeks after birthing).
- Fly season: clean dung piles regularly and use traps around the barn.
September 69° / 41°F
- Breeding window for next year's crias (rebreed females 2–4 weeks after birthing).
- Secure winter hay: about 17 small square bales per alpaca per year here — test a sample before buying.
- Winter prep: install water heaters, repair shelters and windbreaks, stock bedding.
- Fly season: clean dung piles regularly and use traps around the barn.
- Toenail check and trim.
October 54° / 32°F
- Freezing nights: keep water open and feed extra hay during cold snaps.
- Vitamin D for crias and juveniles (ask your vet about product and dose).
November 42° / 23°F
- Freezing nights: keep water open and feed extra hay during cold snaps.
- Vitamin D for crias and juveniles (ask your vet about product and dose).
- Toenail check and trim.
December 34° / 16°F
- Freezing nights: keep water open and feed extra hay during cold snaps.
- Vitamin D for crias and juveniles (ask your vet about product and dose).
Key recommendations
- Shearing: June.
- Best months for crias to be born: May–Aug (breed in Jun–Sep).
- Heat precautions: rarely needed — still provide shade and water.
- Barber pole worm season: Jun — run fecal egg counts every 4–6 weeks in these months.
- Freezing nights: Oct–Apr — keep water from freezing.
- Vitamin D for crias: Oct–Mar.
- Grazing season: May–Sep (about 5 months); feed hay the rest of the year.
- Meningeal worm: Meningeal worm is not established in this region.
- Selenium: Most forage here supplies adequate selenium, and some western areas have high-selenium plants — avoid stacking selenium supplements.
Tools: heat-stress calculator · winter hay calculator · due-date calculator · parasite control guide.
Alpaca farms & shops nearby
No alpaca farms near Sweet Grass County, Montana are mapped on OpenStreetMap yet. If you keep alpacas here, consider adding your farm to OpenStreetMap — it will appear on this page after the next update.
Frequently asked questions
Can you raise alpacas in Sweet Grass County, Montana?
Yes. Alpacas are kept successfully in most climates with good management. Sweet Grass County, Montana scores 98/100 (excellent) on our alpaca climate comfort scale.
When should alpacas be shorn in Sweet Grass County, Montana?
Plan shearing for June, once nights stay above about 38°F (3°C) but before summer heat builds.
What is the best time for crias to be born in Sweet Grass County, Montana?
Mild months suit newborn crias best — here that is May–Aug. For births then, breed females in Jun–Sep (gestation is about 335 days).
How much hay does an alpaca need per year in Sweet Grass County, Montana?
With roughly 7 months of little or no grazing, plan on about 833 lb (378 kg) — around 17 small square bales — per adult alpaca per year, plus waste.
Nearby counties
Coordinates 45.811, -109.945 · land area 1,856 sq mi. Long-term averages, not forecasts. See methodology and data sources. Back to Montana.