Date: 201706
Local time of day: 1201-1800
Location: LAS.Airport, NV
Flight conditions: VMC
Weather elements / visibility: Windshear
Light: Daylight
Aircraft: Airbus 318/319/320/321 Undifferentiated
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
ATC / advisory: Ground LAS
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Workload; Distraction; Communication Breakdown; Situational Awareness
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: Pre-flight
Result: Flight Crew Took Evasive Action; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Requested ATC Assistance / Clarification; General Flight Cancelled / Delayed
Contributing factors: Human Factors; Weather; Procedure; Airport
Primary problem: Procedure

Narrative: Vectors on approach to LAS; I picked up the ATIS; winds were reported V4 (variable at 4 KTS.) Vegas Approach Control; who had us on a vector to later intercept the LOC; reported winds at 230 at 19 KTS gust to 23 KTS. I questioned the Controller about the discrepancy in wind reporting. His response was similar to 'No one would like more accurate ATIS than me.' We landed; taxied in; prepared to depart.I picked up ATIS during preflight and the winds were listed on ATIS as 'V3' (variable at 3 KTS) but the temperature was 46 degrees C. In checking performance for 46 degrees; our flight planning showed we could only take-off from RWY 07L. I called Ground Control to query the winds and ask about using 07L for takeoff. Ground Control reported winds to be something like 250 at 12 KTS. Much different than ATIS reporting V3 KTS. For any of the actual wind reports that were human reported; all wind checks reporting a greater than 10 KT wind out of west; which exceeds the tailwind limitation from Airbus. For the next 2 hours our Dispatcher who was reading the inaccurate winds in METARs; via ATIS; put pressure on pilots to depart from 07L; regardless of our wind readouts from Ground Control over the radio. The Dispatcher put pressure on LAS station crew to get us to depart also; even though the actual winds exceeded an aircraft limitation.We would not have had undue pressure to depart if LAS ATC had listed accurate winds on ATIS. The afternoon winds in LAS are always gusty; from the west. I hope someone will correct this error to keep from pilot-pushing to occur.

Callback: The reporter stated because METAR is legal weather; the flight's dispatchers attempted to force the crew to depart on Runway 07L. The crew checked METAR and Ground Control weather regularly but refused to depart until after a 6 hour ground delay for acceptable temperature. At 13;000 pounds overweight for Runway 07L; Dispatch pressure was unacceptable. The entire issue resulted from METAR inaccuracy; 10 knots or more difference and an actual tailwind. This report was not submitted through the reporter's company to ensure the issue made public which may not always otherwise be the case.



Synopsis: Airbus First Officer reported LAS temperature at 46C with winds 230 at 12 kts. The crew could only accept Runway 07L. Dispatch had METAR winds variable at 3kts; so was forceful about a legal 07L departure but the crew refused a tailwind departure.