We’re 20 days into May and Canberra has had no nights where the mercury has fallen to 0°C or lower, in a month where it historically happens around eight times.

In the first 20 days of May 2026:

Canberra’s lowest minimum has been 0.4°C, which has occurred three times.

Canberra’s average minimum so far this month has been a mild 5.9°C, which is around three degrees above the long-term average.

Canberra’s warmest night this month was May 4, when the minimum of 14.3°C was within 0.8°C of the city’s warmest May night in 87 years of records.

Despite the relatively mild May minimums, Canberra locals have reported light frost on their lawns some mornings.

That’s because it’s usually a couple of degrees colder at grass level than where temperatures are measured by thermometers inside a Stevenson Screen, around two metres above the ground.

Nonetheless, this has been a very mild May in Canberra both by day and by night, with maximums also trending around two degrees above normal.

Why have May nights been so warm in Canberra?

Often, warm minimums are a sign of cloudy skies and rain. But that hasn’t really been the case for most of this month to date.

Indeed, Canberra had received just 0.6mm of precipitation up until May 17, before a total of 21.2mm fell in the three days to 9am this Wednesday, May 20.

The main reason Canberra has been so warm is that the continent has been free of influxes of cool air from the south, due to a series of blocking high pressure systems.

A cool, southwesterly flow is established over the southeast corner of the continent this Wednesday, but it appears that it won’t quite be cool enough for freezing temperatures in the national capital overnight, with minimums of 2°C and 1°C forecast for Thursday and Friday mornings respectively.

Canberra’s minimums should warm up a few degrees into the weekend and the early part of next week, which means it’s now conceivable that the city could go the whole month without hitting sub-zero temperatures.

While this has happened three times since weather records were first kept in the capital in 1939 (most recently in 2007), statistics from the last three years illustrate just how exceptional it would be.

In May 2025, Canberra had seven mornings with a minimum of 0°C lower, with a monthly low of -3.9°C.

In May 2024, Canberra had 10 mornings with a minimum of 0°C or lower, with a monthly low of -4.9°C.

May 2023 was a particularly chilly month in Canberra, with 18 mornings with a minimum of 0°C or lower, and a monthly low of -5.4°C.