B737-800 flight crew reported a pressurization problem during climb that resulted in a diversion.

Attributes
ACN	1693094
Time
Date	201910
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Component
Aircraft Component	Pressurization System
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Total 22000
Person 2
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy

Narrative:

On departure passing approximately 11;000 feet; we had cabin pressure failure and got a cabin altitude warning light and horn. I was flying; disconnected the autopilot and immediately reversed climb to get down to 10;000 feet cabin. We [advised ATC] and got vectors back to ZZZ for an uneventful landing on runway xxc.according to maintenance in ZZZ; problem may have been caused by rapid change of temperature gradient overnight on the ground. I have never heard of this issue. They ran 4 tests on both pressure units and we pressurized the cabin at the gate to approximately 3.0 differential. Log book signed off and an uneventful takeoff and flight to ZZZ1.

Original NASA ASRS Text

Title: B737-800 flight crew reported a pressurization problem during climb that resulted in a diversion.

Narrative: On departure passing approximately 11;000 feet; we had cabin pressure failure and got a CABIN ALTITUDE WARNING light and horn. I was flying; disconnected the autopilot and immediately reversed climb to get down to 10;000 feet cabin. We [advised ATC] and got vectors back to ZZZ for an uneventful landing on Runway XXC.According to maintenance in ZZZ; problem may have been caused by rapid change of temperature gradient overnight on the ground. I have never heard of this issue. They ran 4 tests on both pressure units and we pressurized the cabin at the gate to approximately 3.0 differential. Log book signed off and an uneventful takeoff and flight to ZZZ1.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.