Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 60; Flight Crew Type 15000
Confusion; Distraction; Human-Machine Interface; Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach
Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem
Aircraft; Human Factors; Weather
We were making a visual approach to Runway XXR in ZZZ. The airport was is sight; while the downwind leg and convective activity was present south and west of the airport. After receiving landing clearance from Tower; a wind check was issued and landing speeds adjusted accordingly. The First Officer (FO) was flying and called for landing Flaps 30. The Before Landing Checklist was accomplished and I did a second wind check. We discussed the new speeds and continued the approach. Shortly thereafter; we received a Too Low Flaps Warning. Upon inspection I discovered that the flaps were in the 25 detention. The flaps were moved to position 30. I considered a go-around; but elected to continue the approach as we were on speed and path and a go-around would have been into the convective activity.Obviously; this was a failure to read and verify the checklist items. While debriefing the event with the FO; we both agreed that the monitoring of the wind/ weather was a factor as we considered our performance on final. Also being in a MAX 8 was a factor as the location of the flap gauge is different than the NG; possibly affecting the visual flow of the checklist items. Other factors were the weather deviations on arrival and non-standard arrival into a visual from the north side of the airport and terrain monitoring. Passenger issues requiring Dispatch coordination and the aircraft being met by Law Enforcement at the gate. It was a very busy flight at the end of a long day.
B737 MAX8 Captain cited fleet differences; and checklist compliance contributing to a Too Low Flaps warning during a visual approach with convective weather also being a distraction.  Procedural deviation was corrected; stability evaluated and approach and landing completed.