Average Equilibrium Moisture Content (EMC) by State
Why Wood Moisture Matters More Than You Think
If you've ever purchased wood that was perfectly flat only to watch it warp, crack, or twist after a few weeks in your shop, moisture was almost certainly the culprit.
Wood is hygroscopic, meaning it constantly gains or loses moisture until it reaches Equilibrium Moisture Content (EMC)—the point where the moisture inside the wood matches the temperature and humidity of the surrounding air.
Understanding your local EMC is one of the best ways to predict how lumber will behave after it arrives at your shop.
What Is Equilibrium Moisture Content?
Equilibrium Moisture Content (EMC) is the moisture percentage that wood naturally stabilizes at when left in a particular environment long enough.
For example:
- Wood in Arizona may stabilize around 6–7% moisture content
- The same piece stored in coastal Florida may stabilize around 13–14% moisture content
Nothing about the wood changed—only the environment.
This is why kiln-dried lumber shipped across the country often changes dimensions after arrival.
Why EMC Matters to Woodworkers
Even properly kiln-dried lumber continues moving until it reaches the moisture level of your shop.
As moisture changes, wood expands and contracts.
This movement can cause:
- Warping
- Bowing
- Twisting
- End checking
- Cracks
- Loose glue joints
- Poor fitting joinery
For woodturners, changes in moisture can also affect:
- Bowl movement
- Natural edge distortion
- Hollow form stability
- Segmented glue joints
- Pen blank dimensions
Typical EMC by State
The following values represent approximate average indoor/outdoor equilibrium moisture contents across each state. Actual EMC varies throughout the year depending on temperature, humidity, elevation, and whether wood is stored indoors. Woods not stored in a climate controlled enviorment usually average 2% to 4% higher.
| State | Average EMC |
|---|---|
| Alabama | 13% |
| Alaska | 11% |
| Arizona | 6% |
| Arkansas | 12% |
| California | 8% |
| Colorado | 7% |
| Connecticut | 11% |
| Delaware | 11% |
| Florida | 13% |
| Georgia | 12% |
| Hawaii | 13% |
| Idaho | 8% |
| Illinois | 10% |
| Indiana | 11% |
| Iowa | 10% |
| Kansas | 9% |
| Kentucky | 11% |
| Louisiana | 13% |
| Maine | 11% |
| Maryland | 11% |
| Massachusetts | 11% |
| Michigan | 11% |
| Minnesota | 10% |
| Mississippi | 13% |
| Missouri | 10% |
| Montana | 8% |
| Nebraska | 9% |
| Nevada | 6% |
| New Hampshire | 11% |
| New Jersey | 11% |
| New Mexico | 7% |
| New York | 11% |
| North Carolina | 12% |
| North Dakota | 9% |
| Ohio | 11% |
| Oklahoma | 10% |
| Oregon | 10% |
| Pennsylvania | 11% |
| Rhode Island | 11% |
| South Carolina | 12% |
| South Dakota | 9% |
| Tennessee | 11% |
| Texas | 10% |
| Utah | 7% |
| Vermont | 11% |
| Virginia | 11% |
| Washington | 11% |
| West Virginia | 11% |
| Wisconsin | 11% |
| Wyoming | 8% |
Why Lumber Moves After Shipping
Imagine purchasing maple blanks dried to 7% moisture content in Arizona.
If they're shipped to Louisiana, where the average EMC is around 13%, the blanks begin absorbing moisture immediately.
That extra moisture causes the wood fibers to swell.
Conversely, wood shipped from the Southeast to Nevada or Arizona begins losing moisture, causing shrinkage that can lead to checking or cracking if the drying happens too quickly.
This isn't poor lumber quality—it's simply wood adjusting to a new environment.
Should You Acclimate Lumber?
Absolutely.
Whenever possible:
- Leave lumber stickered for several days or weeks.
- Store it where it will ultimately be used.
- Measure moisture with a quality moisture meter before machining.
- Allow rough-turned bowls to equalize before final turning.
Even kiln-dried lumber benefits from acclimation.
Tips for Buying Wood Online
If you're purchasing turning blanks or lumber online:
- Know the average EMC where you live.
- Expect wood to adjust after shipping.
- Let lumber acclimate before milling.
- Store wood in a stable environment.
- Recheck moisture before final machining.
A little patience can prevent expensive mistakes.
Final Thoughts
Wood is always moving. Even the best kiln-dried lumber continues exchanging moisture with the surrounding air until it reaches equilibrium.
By understanding your local Equilibrium Moisture Content, you can better predict wood movement, reduce defects, and build projects that stay stable for years.
Whether you're turning bowls, building furniture, or stocking your wood rack, knowing your local EMC is one of the simplest ways to improve your woodworking results.
