Frostline.info

Frost line depth in Hamlin, TX 79520

Frost can reach about 10 inches deep in typical soil here (9″ in clay to 13″ in sand). Local codes in climates like this commonly set footing depth at 12 to 18 inches.

Shallow frost
Estimated frost depth
10″
typical silt/loam soil
Typical code footing depth
12–18″
rule of thumb for this climate
Design freezing index
107
°F-days, 100-year winter
Mean annual temp
63.9°F
nearest stations
10″ 0″12″24″36″ ground frozen
Est. frost (typical soil) Typical code footing depth Clay–sand range

Frost depth by soil type

Soil typeEst. frost depth
Sand / gravel (drains well)13″
Silt / loam (typical yard soil)10″
Clay (holds water)9″

Estimates use the modified Stefan equation with a turf / light-snow surface. Bare, plowed or paved ground freezes deeper; deep snow cover keeps frost shallower. How we calculate this.

Verify before you dig. These are climate-based estimates. The legally required frost depth is the figure your building department publishes in its IRC Table R301.2 (climatic and geographic design criteria). Call the Jones County building or permitting office in Texas and call 811 before digging.

What this means for your project in Hamlin

Deck footings & piers

Footings must bear below the frost line and at least 12″ below undisturbed ground. For planning in this area, budget for holes around 18″ deep until your permit office confirms the exact figure.

Fence posts

Set posts at least one-third of their above-ground height. Where frost heave is a problem, carry concrete footings below the frost line (about 12″ here in typical soil) and bell or taper the bottom.

Water & irrigation lines

Bury supply lines below the frost depth. Your water utility or plumbing code sets the minimum cover; freezing is rare, but exposed pipes still need insulation.

Slabs & frost-protected foundations

Frost-protected shallow foundations (IRC R403.3) use the 100-year air freezing index — 107 °F-days here — to size perimeter insulation, letting footings sit shallower than the frost line.

Weather data behind this estimate

NOAA weather stationDistance100-yr AFI
Haskell, TX30.3 mi130
Roscoe, TX37.9 mi87
Abilene, TX41.2 mi86

79520 ranks #4 of 6 ZIP codes in Jones County for frost depth (1 = deepest).

Nearby ZIP codes

All of Jones County →

Common questions

How deep is the frost line in Hamlin, TX?

Based on NOAA's 100-year air freezing index of 107 °F-days for 79520, frost can reach about 10 inches in typical soil, 9 inches in clay and 13 inches in sand or gravel.

How deep do deck footings need to be in 79520?

Footings must sit below the local frost line and at least 12 inches below undisturbed soil. In climates like Hamlin, codes commonly set the depth at 12 to 18 inches. The Jones County building department sets the exact requirement.

Why does soil type change the frost depth?

Wet clay holds a lot of water, and freezing that water releases heat that slows the frost. Dry sand and gravel hold little water and conduct cold faster, so frost goes deeper.

Where does this data come from?

Freezing-index values come from NOAA National Climatic Data Center station records (1951–80), the same data behind the air-freezing-index map in the International Residential Code. We average the three nearest stations, weighted by distance.