It's a subsidence inversion. I was thinking the same as PD when I checked the dewpoints of the alpine sites.
Perisher touching -30 now.

Jindabyne Ap also dropped to almost -9 this morning, must be some burst pipes down that way this morning!

At 9 am it's a bit below -1 and a huge fog in Bathurst - it's quite cold out there.

Interestingly our June min temp mtd (+3.0) is about 4 degrees warmer than the whole May avge min temp which was minus 0.7

We've had so much cloud cover this month spilling over from the east much of the time, it's kept our nights warmer.

Yep, can't see much on here:

http://www.centralwestflying.com/wx/bthwc.php

In these conditions, places like Lake George can harbour fog the entire day, especially with an approaching warm "front" from the NW.

Obs Hill has a backup gauge and its readings will be substituted during the problem period. More generally, very small rainfall amounts are prone to two separate problems. One is spurious 0.2mm tips in the tipping bucket rain gauge (sometimes these might be from debris - I was once 50 metres away from a gauge when one happened so knew that it had probably been caused by a stone thrown into the gauge by a passing lawnmower), but a bigger one is that manual sites chronically under-report small rainfall amounts - I did a study on this some years back and estimated that somewhere between 50-70% of all daily rainfall totals less than 1mm were not reported. For this reason if I was doing any serious analysis involving rain day counts I would use a threshold of 1mm (at least).

-6.3c in Canberra this morning. I must have had my worst frost too, the nasturtiums had that horrible cooked-vegetable look, and you could smell them. They were still frosty, will probably be a blubbery mass tonight. Sigh. At least I had sun, down in Canberra it's all foggy and dull. the local news site is asking people for pictures of the frost: http://the-riotact.com/5-4/75699

My weather thing said 2.4c was the lowest temperature, it evidently didn't catch the cold air flowing down the hill (to the nasturtiums).

-4.9C here easily the coldest day of the year for us so far, the back garden is normally protected from the severe frosts but not last night or this morning, it was already below -1C @ midnight. Quite foggy too in some areas of Canberra and this cloud cover is limiting any heating from the sun so I hope that clears soonish...

Teddy

I got home lateish last night and there was a soft SE breeze blowing, so I hoped it would be OK. Evidently the breeze stopped at some point!

Can see the sun trying to poke through the fog here so any minute now... the sun was doing a good job up my way, car windscreen was all melted and the car was quite warm (I park it where the first dawn rays will hit it on frost-risky nights).

Local paper seems to have a nice selection of frost/ice pictures, here:
http://www.canberratimes.com.au/act-news/canberras-coldest-morning-for-2012-20120620-20mtq.html

Ant do you have a RH reading?, mine is now 19% lowest for the year!.

Still super foggy here in Bathurst - temp about 2 or 3 degrees atm.

Not an overly cold start to today but it has not become much warmer.

If it does not get windy, we may not get a full clearance of the fog at all today.

Still only 2.7 degrees, fog lifting a bit now but no blue sky and still very hazy. Temp all the way up to 2.7 now.

We have sun breaking through - now watch the temp head northwards.

Up here its been tee-shirt weather since about 10am. The sun is so hot when the RH is low like this and little wind.
PS still frost in shady areas at the same time.

No, I'm at work and the console is all by itself. The weather station outside here reckons 54%, which is what I'd expect too, with all the fog and frost evaporating, and SE winds.

Sun came out a few hours back and is blazing away, we are at a tropical 10.2c.

RH here bottomed at 16% at 2pm which is one of the lowest I have ever seen. Ant I would expect that up at your place the RH would also be very low, like the other peaks. Cooma airport is also very dry this afternoon 18%. Still had some frost in the yard at 3pm.

Looking at the console now, I had a fight with it a while back, poked the wrong bit and from then-on it would sound an alarm whenever the outside humidity hit some magic number (usually in the early hours of the morning) so I kept prodding it until it finally gave up (took it weeks), but now it won't show the outside humidity unless it feels like it (and not tonight). Inside's quite high though. Barometer's been plummeting through the day evidently. Incoming thingy seems to be exciting it.

I might put the console outside and see if it will show me what the humidity is there.

Didn't work. It's higher outside!

Amazing that you had frost in the yard PD after a max of 10.0 (we had 10.4 here)
That sun did feel warm as the afternoon went on - felt very warm around 2-3pm.
An unusual feel today & the RH (bottomed out here at 25%) & dew point values confirm that. Very interesting that the sun seems to feel warmer when the humidity is low (though there is probably a completely logical scientific explanation for this phenomenon). My mate from Sydney reckons that the Upper Blue Mountains are cold & damp - sometimes our temps aren't that low compared to other areas but maybe he is onto something.
I lived in England for 6 years so doesn't feel that cold & damp to me.

The wind is really getting up here. Been in the 20s, now into the 30s, (edit mid 30s) and swinging W-NW-N. And the temperature has been going up for a while now. It's 5c so maybe we had our minimum a while back (3 point something). (5.1c now... tomorrow might be quite balmy before the rain arrives).

Huh, here's me skiting and down in Canberra, it's 7.3c!