COLD SOAKED FUEL FROM INBOUND FLIGHT RESULTS IN FROST FORMING ON UPPER SURFACE OF B737-700 WING ON SUBSEQUENT DEPARTURE.

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FLT ARRIVED IN SNA WITH AN INBOUND FUEL LOAD OF 14.9. FLT HAD BEEN AT FL390 WITH AN OAT OF -60 C OR COLDER. FROST WAS NOTED BY THE FO DURING WALKAROUND TO BE WITHIN LIMITS ON THE LOWER WING SURFACE. WE ADDED FUEL FOR OUR DEP TO 19.8. PUSH BACK WAS ACCOMPLISHED AT XA50. AFTER STARTUP THE FLT ATTENDANTS CALLED WITH A PAX'S CONCERN OF FROST ON THE TOP SIDE OF THE WING. WITH ENGS RUNNING; THE FUEL TEMP WAS NOTED AT 0 C. WE CONFIRMED THE FROST AND RETURNED TO GATE. MAINT CTL WAS CONTACTED AND CONTRACT SERVICES CREW ARRIVED AND VERIFIED FROST. NO DEICE EQUIP WAS AVAILABLE. CONTRACT SERVICE PROVIDES DEICING USING PRESSURIZED HOT WATER. GND CREWS REMOVED THE FROST FROM OUR ACFT UPPER AND LOWER SURFACES WITH THIS METHOD. WE ADDED ADDITIONAL FUEL TO FURTHER INCREASE THE FUEL TEMP. CONTRACT MAINT AND MYSELF CONDUCTED THE NUMEROUS INSPECTIONS OF THE UPPER AND LOWER SURFACES TO ENSURE THE WATER USED FOR DEICING DID NOT FREEZE AND THAT ENVIRONMENTAL FROST DID NOT FORM. FLT DEPARTED AT XC30 WITH A CLEAN WING. FUEL TEMP AFTER STARTUP WAS NOTED AT +4 C. OAT WAS 14 C. TANKERING FUEL INTO STATIONS MUST CONSIDER DEICE CAPABILITIES; TEMPS AT CRUISE ALTS; OAT; AND PRECIP AT SAID STATIONS. TIME OF DAY AND TEMP DEWPOINT SPREADS MAY ALSO BE CONSIDERED. FURTHER; FLT CREWS MUST CONSIDER THE UPPER SURFACES ANY TIME A COLD SOAKED WING IS ENCOUNTERED.