What is the deal with the Longmire Gate ?

Is it closed nightly or is it only closed if there is accumulation of over 3 inches.
What is the deal and what is the average time it gets open ?

If you would pay attention in Forest Service/National Park: Policies and Shortcuts class, you'd know the answer already...jeez.

Is it closed nightly or is it only closed if there is accumulation of over 3 inches.
What is the deal and what is the average time it gets open ?

call 360-569-2211 and key thru the menu and it will tell you the nightly closing time and the highly unreliable opening time.  I believe the policy on opening time is 9 a.m., but that generally means 9-10 a.m. or so and if it snows, all bets are off; sometimes they'll state an anticiplated 10 or 11 or 12 opening, but when they do that, be prepared (psychologically and physiologically) to wait, cuz things can get tense at Longmire.

P.S.: if there is a heavy snow storm/blizzard they will close the gate; if you are in the vicinity of the parking lot at Paradise they will ask you to leave. If you are in the backcountry and make it back out, they will leave a note on your car; I came out once in a blizzard to an eerily totally empty parking lots and my snow encrusted truck, found the note, and also found Ranger/LEO Karen (now retired) waiting for me at Cougar Rock (in violation of policy) just cuz she was worried

For those who may not know the winter drill, the Longmire gate is locked nightly, whether it snows or not.  This is for traffic safety & law enforcement.  Overnight parking requires a permit & you'll be gleefully plowed in if you're not in the designated area. 

The uphill gate is usually swung about an hour before dark.  You may be snowed in, but don't worry about being locked in if you're late.  They will leave a note with the latest gate combo.  Like Andy, I've many times found the sweep ranger patiently waiting at the parking lot for this last samurai long after the plows were gone.  I do wish the NPS would spring for a new lock with luminescent dial.  They probably usually use their keys, but those worn  number brass tumblers are hard for a geezer on a stormy night.

Twenty-four hour access resumes when the Paradise Inn reopens, usually late May. This is the best time for 'light & fast' on many alpine routes.

If you call from below Elbe, you can bail to White Pass if the gate seems too slow.  I think the phone message has improved in recent years.  It's usually updated just after 7AM. One can go directly to the road report by dialing 1, pause 1, pause 2 as soon as the recording begins.  Mondays & Tuesdays seem even slower than average; probably many staff are off after the weekend.  The estimated opening time seems fairly reliable when given as 7, 8, or 9 AM.  Bring a book, frisbee or XC gear & be prepared for long delays or non-openings when the Paradise telemetry shows a foot or more of new snow.  High winds tend to drift snow into the lots and cause further delays.  Eagle Peak, Mildrid Point, Mt. Ararat & Mt Beljica are feasible backup destinations for strong parties when the gate does not open and there is sufficient forest snowpack.

Plowing begins (at the entrance, if necessary) at 6 AM and it's not uncommon to see the plows reaching the Paradise lot on the webcams several hours before the road actually opens.  I think the parking lots are about half the job & in recent years the managers seem to insist on total clearing of these before the gate swings.  Sure would be nice if they'd let the first fifty cars up to Narada while they finished Paradise.  Some think the late openings are to keep the masses within easy rescue range,

Speaking of Narada, Tatoosh fans take warning:  The heated comfort station looks to be closed for the winter...     
Oh, and the Nisqually footlogs are gone at Cougar Rock, so we can't even hoof it up the Wonderland Trail when the gate is closed...