Canberra appears certain to break its record for the warmest average maximum temperatures in July since records began in 1939, while enduring a near-record run of frosty nights.

Let's deal with those warm days first because July 2023 has been dry in the national capital, and exceptionally mild during daylight hours.

• As things stand now counting the max temp on July 25, the running average max for July 2023 is 14.1°C
• That's 0.4°C warmer than the old record of 13.7°C in 2019.
• Canberra's average July maximum is 12.7°C

A beautiful fog bow this morning with our big dish, Deep Space Station 43.🌈📡🌫️ -3°C#FogBow #DSS43 #weather pic.twitter.com/7XrMRLy9Kj

— CanberraDSN 📡 (@CanberraDSN) July 25, 2023

With less than a week remaining until the end of July and relatively warm northwesterlies buffeting the city on Sunday, there's no end to the unseasonably warm days in sight. The maximum temps forecast for Canberra until the end of the month are:

• July 26: 16°C (today)
• July 27: 16°C
• July 28: 15°C
• July 29: 17°C
• July 30: 18°C
• July 31: 17°C

And based on forecasts for the next six days, the running average max could end up in the mid-14 degree range, breaking the old record by close to a full degree.

But as mentioned, nights are another story...

Canberra has been locked in a pattern of dry days with minimal rainfall (see down the page for rainfall stats) and cold frosty nights.

Frost is of course hardly newsworthy in Canberra. With an average July minimum of 0.1°C, you expect frost more nights than not, especially when you factor in that temperatures at grass-level are usually a degree or two colder than the official air temp.

Usually, Canberra gets a break from frost after a few nights as rain-bearing weather systems move through the ACT, raising the humidity and night-time temperatures. Not so much this July.

• As things stand this Wednesday, Canberra has just had its 11th consecutive night below zero, after a low of -5.3°C this morning.
• Thursday morning also looks like a frosty one, meaning it'll be 12 straight nights of subzero temps before Friday morning potentially stops the run with a forecast min of 1°C.
• In the last 30 years, Canberra has had just four streaks of subzero minimums lasting longer than 10 nights (in any month or combo of months). The longest were 14 nights in 1994 and 2002.
• Canberra's running minimum for July 2023 to date, as of Wednesday morning, was -0.6°C

Lack of rainfall is also a factor here

Canberra has had just 9.2 mm of rain for the month to date, due largely to rain-bearing frontal systems staying well south of the Australian mainland. This is also why the snowfields have barely had a top-up of late.

The good news for Canberra water storages is that this is the first month this year when rainfall has not reached the monthly average.

Indeed as the graph above shows, July 2023 is just the second month in the last 12 months with below-average rainfall.