Climate snapshot for alpacas
90/100Alpaca climate comfort score
86°FAverage high, Jul
13°FAverage low, Jan
~13Days above 90°F (32°C) per year
~182Frost nights per year
16 inAnnual precipitation
2Barber pole worm months
16Hay bales / alpaca / year
Main challenges
- Hard winters — average lows under 15 °F in Dec–Jan
Advantages
- Summers rarely reach heat-stress levels for alpacas
- Short or no barber pole worm transmission season
- Low meningeal worm risk
Overall rating: 90/100 — 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 | 13°F | 0.7 in | 95 · ok | frost |
| Feb | 37°F | 15°F | 0.7 in | 105 · ok | frost |
| Mar | 48°F | 23°F | 1.0 in | 109 · ok | frost |
| Apr | 56°F | 31°F | 1.9 in | 107 · ok | frost |
| May | 65°F | 40°F | 2.7 in | 121 · ok | worms, grass |
| Jun | 75°F | 49°F | 2.3 in | 127 · caution | worms, grass |
| Jul | 86°F | 55°F | 1.3 in | 127 · caution | grass |
| Aug | 84°F | 53°F | 0.9 in | 132 · caution | grass |
| Sep | 73°F | 44°F | 1.4 in | 120 · ok | grass |
| Oct | 58°F | 32°F | 1.6 in | 102 · ok | grass |
| Nov | 45°F | 22°F | 0.8 in | 106 · ok | frost |
| Dec | 35°F | 14°F | 0.7 in | 90 · 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 Big Horn County, Montana
January 35° / 13°F
- Hard cold: extra hay at night, heated water, windbreaks and coats for crias or seniors; check ears for frostbite.
- Vitamin D for crias and juveniles (ask your vet about product and dose).
- Toenail check and trim.
February 37° / 15°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 48° / 23°F
- Book your shearer now — spring calendars fill up fast.
- 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 56° / 31°F
- Run pre-season fecal egg counts so you know each animal's baseline.
- 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 65° / 40°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.
- Spring grass: switch from hay to pasture gradually over 1–2 weeks and monitor body condition.
- Toenail check and trim.
June 75° / 49°F
- Warm spells possible — watch for open-mouth breathing in heavy-fleeced or dark animals.
- 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 86° / 55°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 84° / 53°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).
- Dry pasture: supplement with hay as grass goes dormant; keep water troughs clean and full.
September 73° / 44°F
- 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.
October 58° / 32°F
- Secure winter hay: about 16 small square bales per alpaca per year here — test a sample before buying.
- Winter prep: install water heaters, repair shelters and windbreaks, stock bedding.
- Vitamin D for crias and juveniles (ask your vet about product and dose).
November 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.
December 35° / 14°F
- Hard cold: extra hay at night, heated water, windbreaks and coats for crias or seniors; check ears for frostbite.
- Vitamin D for crias and juveniles (ask your vet about product and dose).
Key recommendations
- Shearing: May.
- 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: May–Jun — run fecal egg counts every 4–6 weeks in these months.
- Freezing nights: Nov–Apr — keep water from freezing.
- Vitamin D for crias: Oct–Mar.
- Grazing season: May–Oct (about 6 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 Big Horn 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 Big Horn County, Montana?
Yes. Alpacas are kept successfully in most climates with good management. Big Horn County, Montana scores 90/100 (excellent) on our alpaca climate comfort scale; the key issues are hard winters.
When should alpacas be shorn in Big Horn County, Montana?
Plan shearing for May, 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 Big Horn 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 Big Horn County, Montana?
With roughly 6 months of little or no grazing, plan on about 766 lb (347 kg) — around 16 small square bales — per adult alpaca per year, plus waste.
Nearby counties
Coordinates 45.408, -107.518 · land area 4,998 sq mi. Long-term averages, not forecasts. See methodology and data sources. Back to Montana.