Tule fog is a winter ground fog that forms in the Central Valley when winds are calm and the air is damp. A garage door is not harmed by one foggy morning, but weeks of damp air can leave moisture on metal parts, stiffen lubricant and expose a worn bottom seal. Check the seal, keep the tracks clean and lubricate the right parts.
Quick answers
Does tule fog damage a garage door?
Not by itself. Repeated damp air can rust bare metal, wear down lubricant and show up any gap at a worn bottom seal, so a seasonal check helps.
Should I lubricate garage door tracks in humid weather?
No. Clopay says to wipe the tracks clean with a damp cloth and not to lubricate them, since lubricant makes the rollers work harder.
When does tule fog season start?
Winter is the season, according to NASA, which describes the fog as forming in colder months when winds are light and the air is moist.
How often should I check the bottom seal?
Clopay suggests about every three months, and it says most seals need replacing every 2 to 3 years depending on climate and use.
The full explanation
What tule fog is and when it comes
NASA describes tule fog as a low, thick ground fog that settles over the San Joaquin Valley in winter. It tends to form after sunset and is thickest just before dawn, when winds are calm and the air has cooled until moisture condenses near the ground. Winter brings more rain and lighter winds, and the San Joaquin and Sacramento valleys are, in NASA's words, fertile territory for fog.
For a garage door, the point is simple. A door in a Central Valley town can spend many winter mornings in saturated air, even on days with no rain at all.
What damp air does to a garage door
Fog does not hurt a steel door on its own. The trouble is what moisture finds. Clopay warns that gaps at the floor let in moisture, and that moisture affects how well lubricant performs. It also notes that dusty or humid conditions can shorten how long lubricant lasts.
- Bottom seal: a cracked or flattened seal lets damp air and water in. Clopay says a failed seal exposes stored items to moisture and lets bugs and rodents in.
- Hinges, rollers and springs: bare metal can pick up surface rust where the lubricant has worn off.
- Wood doors and trim: bare edges soak up moisture, so check the paint and sealant at the bottom edge.
- Stored items: cardboard, paper and tools kept near the door feel the damp first.
What to check by season
| Season | What the weather does | What to check |
|---|---|---|
| Late fall | First rains come and the fog season starts | Bottom seal for cracks, hardening or flattening; floor contact |
| Winter | Fog on many mornings, cool nights, light winds | Hinges and rollers for rust; stored items; moisture marks at the bottom edge |
| Late winter | Damp spells continue between clear days | Re-lubricate hinges, rollers and springs if the door has gone noisy or stiff |
| After the season | Air dries out | Clean the tracks and look for any remaining rust spots |
A simple seasonal guide for Central Valley homes. Check your own door and your owner's manual.
A short upkeep routine for foggy months
Look at the bottom seal
Close the door and look along the floor. Clopay says to replace seals that are cracked, crushed or no longer springing back, and to inspect them about every three months.
Wipe the tracks, do not oil them
Clopay says to wipe the tracks with a damp cloth to remove dirt and debris, and not to lubricate them, because lubricant makes the rollers work harder.
Lubricate the moving parts
Use a silicone-based lubricant on hinge pins and on the springs, and wipe off the excess. If your rollers are nylon, Clopay says not to apply lubricant to them.
Run the door
Open and close it by hand with the opener released, or with the opener on. A door that moves smoothly and quietly is in good shape. See what to use as lubricant.
Stop if it feels wrong
If the door feels heavy, scrapes, or is crooked, do not keep using it. Springs and cables are under high tension, so leave them to a technician.
Fog and the opener
Fog itself does not stop an opener. If the door acts up on a damp morning, look for the usual causes first: a seal that has stuck to the floor, a dirty track or a stiff roller. NWS Hanford, according to NASA, advised drivers in dense fog to slow down and use dimmed headlights, so give yourself light and time when you leave the garage in the dark. For a full seasonal list, see our garage door maintenance checklist.
Where we come in
Emil Garage Doors repairs garage doors, openers and gates in Southern California, and our city pages cover California. If your seal is worn or your door is stiff after a foggy winter, we repair garage doors in Delano, Hanford and Lodi. Our 12-point safety inspection is $89. Call (213) 340-4232 or use the estimate form on this page. See garage door repair.
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Keep reading
Sources
- NASA Earth Observatory, Cool Yule Tule (tule fog in the San Joaquin and Sacramento valleys)
- NASA Earth Observatory, Fog and Haze in California's San Joaquin Valley
- Clopay: How to properly lubricate garage door components
- Clopay: Garage door seals, a buyer's guide
- Clopay: How bad is it to not replace a worn bottom weather seal?