Climate snapshot for alpacas
90/100Alpaca climate comfort score
89°FAverage high, Jul
38°FAverage low, Dec
~40Days above 90°F (32°C) per year
~22Frost nights per year
32 inAnnual precipitation
1Barber pole worm months
13Hay bales / alpaca / year
Main challenges
- Summer heat — heat-stress precautions needed in Jul–Aug
Advantages
- Practically frost-free winters
- A long grazing season (8 months of grass growth)
- 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: Hot-summer Mediterranean (Köppen Csa).
Month-by-month climate
Average highAverage lowPrecipitation
| Month | High | Low | Precip. | Heat-stress index | Notes |
|---|---|---|---|---|---|
| Jan | 56°F | 38°F | 6.4 in | 137 · ok | grass |
| Feb | 60°F | 40°F | 6.2 in | 141 · ok | grass |
| Mar | 64°F | 42°F | 4.5 in | 140 · ok | grass |
| Apr | 69°F | 44°F | 2.0 in | 141 · ok | worms, grass |
| May | 76°F | 49°F | 1.1 in | 130 · caution | grass |
| Jun | 84°F | 54°F | 0.2 in | 120 · caution | — |
| Jul | 89°F | 57°F | 0.0 in | 117 · ok | — |
| Aug | 89°F | 56°F | 0.0 in | 121 · caution | — |
| Sep | 86°F | 54°F | 0.1 in | 125 · caution | — |
| Oct | 77°F | 49°F | 1.4 in | 119 · ok | grass |
| Nov | 64°F | 42°F | 3.1 in | 127 · ok | grass |
| Dec | 56°F | 38°F | 6.6 in | 136 · ok | grass |
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 Napa County, California
January 56° / 38°F
- Book your shearer now — spring calendars fill up fast.
- Breeding window for next year's crias (rebreed females 2–4 weeks after birthing).
- Vitamin D for crias and juveniles (ask your vet about product and dose).
- Toenail check and trim.
February 60° / 40°F
- Vitamin D for crias and juveniles (ask your vet about product and dose).
March 64° / 42°F
- Shearing month: shear the whole herd, and trim toenails, check teeth and body condition while animals are restrained.
- Run pre-season fecal egg counts so you know each animal's baseline.
- Toenail check and trim.
April 69° / 44°F
- Barber pole worm season: fecal egg counts every 4–6 weeks, check eyelid color, pick up dung piles twice a week.
May 76° / 49°F
- Warm spells possible — watch for open-mouth breathing in heavy-fleeced or dark animals.
- Secure winter hay: about 13 small square bales per alpaca per year here — test a sample before buying.
- Fly season: clean dung piles regularly and use traps around the barn.
- Toenail check and trim.
June 84° / 54°F
- Warm spells possible — watch for open-mouth breathing in heavy-fleeced or dark animals.
- Dry pasture: supplement with hay as grass goes dormant; keep water troughs clean and full.
- Fly season: clean dung piles regularly and use traps around the barn.
July 89° / 57°F
- Heat precautions: shade, airflow, cool fresh water and no handling in the heat of the day.
- Dry pasture: supplement with hay as grass goes dormant; keep water troughs clean and full.
- Fly season: clean dung piles regularly and use traps around the barn.
- Toenail check and trim.
August 89° / 56°F
- Heat precautions: shade, airflow, cool fresh water and no handling in the heat of the day.
- CDT boosters for females due next month; prepare a clean birthing paddock and birthing kit.
- Dry pasture: supplement with hay as grass goes dormant; keep water troughs clean and full.
- Fly season: clean dung piles regularly and use traps around the barn.
September 86° / 54°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.
- Dry pasture: supplement with hay as grass goes dormant; keep water troughs clean and full.
- Fly season: clean dung piles regularly and use traps around the barn.
- Toenail check and trim.
October 77° / 49°F
- 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).
- Spring grass: switch from hay to pasture gradually over 1–2 weeks and monitor body condition.
- Fly season: clean dung piles regularly and use traps around the barn.
November 64° / 42°F
- 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).
- Vitamin D for crias and juveniles (ask your vet about product and dose).
- Toenail check and trim.
December 56° / 38°F
- 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).
- Vitamin D for crias and juveniles (ask your vet about product and dose).
Key recommendations
- Shearing: March.
- Best months for crias to be born: Sep–Dec (breed in Oct–Jan).
- Heat precautions: Jul–Aug.
- Barber pole worm season: Apr — run fecal egg counts every 4–6 weeks in these months.
- Winter: frost is rare.
- Vitamin D for crias: Nov–Feb.
- Grazing season: Oct–May (about 8 months); feed hay the rest of the year.
- Meningeal worm: Meningeal worm is not established in this region.
- Selenium: Selenium levels vary across the state. Test hay or blood before changing supplements.
Tools: heat-stress calculator · winter hay calculator · due-date calculator · parasite control guide.
Alpaca farms & shops nearby
Places mapped on OpenStreetMap with “alpaca” in their name, within about 80 km (50 miles). Contact them before visiting — opening times change.
| Name | Type | Distance | Website |
|---|---|---|---|
| Mad Alpaca Games · Davis | shop | 32 mi | — |
| Alpaca Fashion | shop | 48 mi | — |
Data © OpenStreetMap contributors. Know a farm that's missing? Add it to OpenStreetMap and it will appear here in the next update.
Frequently asked questions
Can you raise alpacas in Napa County, California?
Yes. Alpacas are kept successfully in most climates with good management. Napa County, California scores 90/100 (excellent) on our alpaca climate comfort scale; the key issues are summer heat.
When should alpacas be shorn in Napa County, California?
Plan shearing for March, 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 Napa County, California?
Mild months suit newborn crias best — here that is Sep–Dec. For births then, breed females in Oct–Jan (gestation is about 335 days).
How much hay does an alpaca need per year in Napa County, California?
With roughly 4 months of little or no grazing, plan on about 632 lb (287 kg) — around 13 small square bales — per adult alpaca per year, plus waste.
How hot does it get for alpacas in Napa County, California?
Heat-stress precautions are needed in Jul–Aug. We estimate about 40 days a year above 90°F (32°C).
Nearby counties
Coordinates 38.507, -122.326 · land area 748 sq mi. Long-term averages, not forecasts. See methodology and data sources. Back to California.