Commercial Fixed Wing
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Distraction
Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Rejected Takeoff
Human Factors; Environment - Non Weather Related; Company Policy; Procedure
While beginning the initial takeoff roll the FO pressed TOGA and we quickly realized the autothrottles had not been armed. We had a very quick discussion of whether or not the before takeoff checklist had been accomplished. Since I always arm the autothrottles during the before takeoff checklist and there was doubt on the checklist being accomplished I made the decision to reject the takeoff and taxi back. We were at taxi speed when this occurred and normal braking was used to exit the runway. We taxied clear; accomplished the checklist and continued the flight as normal. Contributing factors were thunderstorms in the area; a new ATIS and two runway crossings during the taxi.The decision to reject the takeoff and make sure the checklist was completed was the safest course of action. I usually check the autothrottles are armed when we receive the takeoff clearance; but didn't this time due to the distractions previously listed. One of the things that always gets covered during the brief these days is the lack of proficiency and the need to be extra vigilant. This event is a good example of that.
As we took to Runway XXR for takeoff in ZZZ; we noticed that the autothrottle was not armed.  We questioned whether we had completed the before takeoff checklist.  Since it was the safest thing to do; we decided to discontinue the takeoff to run the before takeoff check.  It was technically an aborted takeoff; but we never brought the power above 40 ish percent and we never got over a brisk taxi speed; maybe 20 knots.  We had to taxi up to Runway YYL to exit so we didn't apply any brakes.  We had several distractions.  We were watching thunderstorms on the radar.  We crossed two runways and we had a last minute ATIS.  Also with the reduced schedules; we don't fly as much any thus tend to carry a little more rust.  The antidote is to slow down and take your time.
Air carrier flight crew reported being distracted and not arming the autothrottle prior to departure resulting in a rejected takeoff.