Date: 202110
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: Windshear
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Airspace: Class C ZZZ
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Time Pressure; Situational Awareness; Communication Breakdown
Second reporter function: Pilot Flying; Captain
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Weather / Turbulence
When detected: In-flight
Result: Flight Crew Overcame Equipment Problem; Flight Crew Overrode Automation
Contributing factors: Human Factors; Weather
Primary problem: Human Factors

Narrative: While on our third leg of the day from ZZZ1 to ZZZ; we received a 'too low flaps' below 500 ft. for not being at planned landing flaps.  We did not execute a go around and configured to final flaps 30; accomplished the landing checklist; and landed safely.  The leg started by being delayed into ZZZ1 on our previous flight and the departing flight being delayed 60 mins.  The flight was a quick XX minutes and we were set up and well briefed for the arrival and approach into ZZZ.  We began configuring to flaps 10 on an extended base leg and slowed to 190 kts. We were subsequently asked to speed up to 210 kts; went back to flaps 5 and given a dogleg to final for a visual to XXR; backed up by the ILS XXR.  Our dogleg had us pointed at the FAF and speed increased in order to sequence in front of other arriving traffic from the west.  We then started to slow and configure to flaps 15 with the gear down at the FAF.  The winds were gusty and had a 15kt wind additive.  The approach was rushed but normal.  At 1000 ft. we were not cleared to land and set missed approach altitude.  We got landing clearance just prior to the 500 ft. call; which was made immediately after acknowledging landing clearance.  We were little fast at the 500 ft. call but stable with gusty winds.  Just below 500 ft. feet we got the 'too low flaps'; recognized the error of being at flaps 15 and configured the jet at flaps 30; accomplished the landing checklist.  Touchdown and landing rollout were normal.  The event was thoroughly debriefed for CRM error / breakdown and the corrective action of a go around was discussed in depth.


Second narrative: On short final into ZZZ during a visual approach backed up by the ILS to XXL we experienced a 'too low flaps' below 500 ft. and failed to go around.  As pilot flying; upon hearing this warning and realizing flaps where still at 15; I called for flaps 30 and the landing checklist electing to land instead of going around. Normal touchdown and rollout.  Contributing factors included late landing clearance in gusty conditions.  Additionally; this was the third leg of a 12 hour duty day.


Synopsis: Air carrier flight crew reported they received a 'too low flaps' warning on approach below 500 feet. The crew elected to not do a go-around and instead configured the flaps correctly and continued to a landing.