When Do OKC Foundations Move Most? A Seasonal Guide
Short answer: OKC foundations tend to move most when soil moisture swings, from a wet spring into a hot, dry summer. NOAA normals show Oklahoma City's rain peaks at 5.31 inches in May and falls to 3.59 inches in July.[42] Clay swells when wet and shrinks when dry, so cracks often open in late summer.[29]
Your foundation sits on soil that changes with the weather. In Oklahoma County, that soil often contains shrink-swell clay.[16] Knowing the seasons helps you know when to look for cracks.
OKC Rainfall by Month (NOAA 1991–2020 Normals)
| Month | Avg. rain (in.) | Month | Avg. rain (in.) |
|---|---|---|---|
| Jan | 1.32 | Jul | 3.59 |
| Feb | 1.42 | Aug | 3.60 |
| Mar | 2.55 | Sep | 3.72 |
| Apr | 3.60 | Oct | 3.32 |
| May | 5.31 | Nov | 1.68 |
| Jun | 4.49 | Dec | 1.79 |
| Year | 36.39 |
Source: NOAA NCEI, Oklahoma City Will Rogers AP.[42]
Season by Season
Spring (March to May): soil swells. Rain climbs from 2.55 inches in March to 5.31 inches in May, the wettest month.[42] Wet clay swells and can push up on slabs. Watch for sticking doors and water pooling by the house.
Summer (June to August): soil shrinks. Rain falls off after June, and July averages a daily high of 93.1°F.[42] OSU Extension notes Oklahoma often has heavy spring rains followed by summer droughts.[44] Dry clay shrinks and pulls away from the slab, so cracks often widen now.
Fall (September to November): uneven recovery. September and October still average over 3 inches of rain each, then November drops to 1.68 inches.[42] Some summer cracks partly close when the rain returns.
Winter (December to February): driest months. January is the driest month at 1.32 inches.[42] Movement is usually slower, but drought can keep soil shrinking.
Why Oklahoma County Soil Matters
OSU Extension says shrink-swell soils are common in many parts of Oklahoma and can crack foundations and walls.[29] USDA soil data shows shrink-swell clay limits slab homes on about 21% of Oklahoma County's mapped land.[16]
What to Do Each Season
- Spring: Clean gutters and make sure downspouts drain away from the house.[30]
- Summer: Keep soil moisture steady during dry spells. See our drought watering guide.
- Fall: Photograph cracks and compare them with your spring photos.
- Any time: If cracks keep growing across seasons, have a pro take a look.
Or call (405) 320-9894
Related Services
More: all guides.
Frequently Asked Questions
What month do OKC foundations move most?
There's no single month. Movement follows soil moisture swings, often as the wet spring (May averages 5.31 inches) turns into a hot, dry summer.[42]
Why do my cracks open in summer and close in fall?
Clay soil shrinks as it dries and swells when it gets wet again, so cracks can widen in summer and partly close after fall rain.[29]
What is the rainiest month in Oklahoma City?
May, with an average of 5.31 inches under NOAA's 1991–2020 normals.[42]
Is Oklahoma County soil expansive?
Much of it can be. USDA soil data shows shrink-swell clay limits slab homes on about 21% of Oklahoma County's mapped land.[16]
How does your free quote service work?
OKC Foundation Repair Experts is a free quote and referral service. We are not a contractor. You fill out the short form, and a local foundation repair company that serves your area contacts you. The request is free, and you never have to hire anyone.
Last updated 2026-10-29.
Sources
Figures are third-party published estimates, not quotes. Retrieved 2026-10-29.
- FoundationSoils – Oklahoma County, Oct 20, 2026 data
- Oklahoma State University Extension – Moving to the Country? (NREM-965), Foundation Problems
- OSU Extension – Minimizing Stormwater Runoff by Disconnecting Residential Downspouts (BAE-1534)
- NOAA NCEI – 1991–2020 Monthly Normals, Oklahoma City Will Rogers AP (USW00013967)
- Oklahoma State University Extension – Preparing Your Lawn for Drought