Title 24 Reports in Tuolumne County

The Highway 108 ladder

Follow the highway east from Sonora and the assignments step like this — heights from USGS data at each community's Census reference point, zones from the Energy Commission table:

• Sonora, about 1,800 feet — 95370, zone 12
• Twain Harte, about 3,600 feet — 95383, zone 12
• Mi-Wuk Village, about 4,400 feet — 95346, zone 16
• Long Barn, about 5,000 feet — 95335, zone 16
• Strawberry, about 5,300 feet — 95375, zone 16

The change falls between Twain Harte and Mi-Wuk Village, and in fact inside Mi-Wuk Village: the Census places 72 per cent of that community's land in 95346, which is zone 16, and the other 28 per cent in Twain Harte's 95383, which is zone 12. Along that stretch the address's own ZIP code settles which side a house is on.

Four mountain ZIP codes

Of the fourteen ZIP codes we derive for Tuolumne County, four are zone 16 — 95335, 95346, 95364 and 95375 — and all of them are in the high country the highway climbs into. Everything else is zone 12. That includes the Sonora area itself, with Columbia and Jamestown. Tuolumne City and Soulsbyville, east of Sonora, are zone 12 as well. So are Groveland and Pine Mountain Lake, to the south off Highway 120.

Sonora is the county's only incorporated city on the California Department of Finance's 2026 estimates, and it is zone 12. Sonora permits work inside its own limits; every other community, the whole Highway 108 climb and the four mountain ZIP codes included, is unincorporated and comes to the county.

Twain Harte against Mi-Wuk Village

The two are about 800 feet apart in height and a few miles apart on the road, yet a house in Twain Harte is assessed on zone 12's hot summers and one in Mi-Wuk Village on zone 16's long heating season. A plan reused from one community for the other is being measured against a target it was not drawn for.

Every ZIP code by zone

Zones per the Energy Commission; county membership and community names per the 2020 Census.

• Climate zone 12 — 95305 (Groveland); 95309; 95310 (Columbia); 95321 (Pine Mountain Lake, Groveland); 95327 (Jamestown, Chinese Camp); 95370 (Sonora, Phoenix Lake, Cedar Ridge, Tuttletown, Mono Vista, Columbia, East Sonora); 95372 (Soulsbyville); 95379 (Tuolumne City); 95383 (Twain Harte, Mi-Wuk Village); also 95329, split with a neighbouring county (below)
• Climate zone 16 — 95335 (Long Barn, Cold Springs, Sierra Village); 95346 (Mi-Wuk Village, Sierra Village); 95364; 95375 (Strawberry)

A ZIP code that crosses the county line

• 95329 — about 45% within Tuolumne County, the remainder in Stanislaus 37% and Mariposa 18%

95329, on the county's southern edge, is the one ZIP code here held by plurality: Tuolumne has the largest share without a majority; Stanislaus and Mariposa counties hold the rest. It counts toward zone 12, but nothing rests on it — the county has nine other zone 12 ZIP codes. The ZIP is zone 12 wherever an address in it falls, and its permit comes from whichever of the three counties the parcel lies in.

Finding the zone for your own project

The zone is set by the project's location and confirmed from the ZIP code against the Energy Commission's published table — not from the county name and not from the nearest large town. Because Tuolumne County contains more than one zone, that check decides which set of numbers a report is written against.

Give us the project address and we determine the zone as part of preparing the report. It is the first thing established, because every insulation, glazing and equipment figure downstream depends on it.

Climate zones in Tuolumne County

Tuolumne County contains California climate zones 12 and 16. The zone drives the insulation, glazing and equipment performance a report has to demonstrate, and it is confirmed from the project ZIP code against the Energy Commission's published table.