Williamtown is a weather station located 8 m above sea level, 16 km from Tarro. Its records go back to 1944: 75 years of temperature are available up to 2025, along with rainfall and a comparison with two reference normals. Over 1991–2020 the annual mean temperature there is 18.1 °C, clearly higher than over 1961–1990 (17.4 °C): a difference of 0.7 °C. The warmest year of the series is 2019 (19.2 °C) and the coldest 1960 (16.7 °C). The last complete year, 2025, ranks 3 out of 75, from warmest to coldest. Over 1961–2025, the annual mean temperature changes by +0.25 °C per decade. The station ranks 49 out of 227 stations, from the fastest rise to the slowest.
Annual mean temperature since 1944
The first ten years of the series (1951–1960) average 17.2 °C; the last ten (2016–2025) average 18.7 °C, a difference of +1.6 °C. Of the ten warmest years in the series, 8 fall after 1999. The warmest is 2019 (19.2 °C). The ten-year running mean peaks at 18.7 °C (2025) and bottoms out at 17.1 °C (1962).
Annual rainfall since 1944
On average 1137 mm of rain falls per year over the 64 documented years. The wettest year, 1963, received 1794 mm; the driest, 1980, only 541 mm, which is 3.3 times less. The 1991–2020 normal (1093 mm per year) is 40 mm (3.5 %) below the 1961–1990 one (1133 mm). Over 1991–2020, June is on average the wettest month (133 mm) and August the driest (56 mm). Between 2000 and 2025, 8 years out of 20 exceeded the series average.
Monthly normals: 1961–1990 against 1991–2020
The table compares, month by month, the mean temperature and the rainfall total of two thirty-year reference periods. The difference column shows what the recent period changes compared with the earlier one.
| Month | Temp. 1961–1990 | Temp. 1991–2020 | Difference | Rain 1961–1990 | Rain 1991–2020 | Difference |
|---|---|---|---|---|---|---|
| January | 22.9 °C | 23.8 °C | +0.9 °C | 112 mm | 77 mm | −35 mm |
| February | 22.6 °C | 23.4 °C | +0.8 °C | 111 mm | 119 mm | +8 mm |
| March | 21.1 °C | 21.5 °C | +0.4 °C | 130 mm | 121 mm | −9 mm |
| April | 18.1 °C | 18.4 °C | +0.3 °C | 119 mm | 101 mm | −18 mm |
| May | 14.7 °C | 15.4 °C | +0.7 °C | 105 mm | 117 mm | +12 mm |
| June | 12.2 °C | 13.1 °C | +0.9 °C | 121 mm | 133 mm | +12 mm |
| July | 11.2 °C | 12.2 °C | +1.0 °C | 62 mm | 75 mm | +13 mm |
| August | 12.2 °C | 13.1 °C | +0.9 °C | 70 mm | 56 mm | −14 mm |
| September | 14.9 °C | 15.8 °C | +0.9 °C | 58 mm | 63 mm | +5 mm |
| October | 17.6 °C | 18.3 °C | +0.7 °C | 83 mm | 70 mm | −13 mm |
| November | 19.7 °C | 20.4 °C | +0.7 °C | 79 mm | 86 mm | +7 mm |
| December | 21.8 °C | 22.2 °C | +0.4 °C | 83 mm | 75 mm | −8 mm |
The largest temperature change is in July (+1.0 °C) and the smallest in April (+0.3 °C); over the year the mean difference is +0.7 °C, and 12 months out of twelve are warmer than before. For rainfall, the largest difference is in July (+13 mm) and the smallest in January (−35 mm).
Records at Williamtown
- Warmest year: 19.2 °C, in 2019
- Coldest year: 16.7 °C, in 1960
- Driest year: 541 mm, in 1980
- Wettest year: 1794 mm, in 1963
- Warmest month: 27.2 °C, in January 2019
- Coldest month: 10.0 °C, in July 1971
- Wettest month: 600 mm, in February 1990
- Hottest day: 45.5 °C, on 11 February 2017
- Coldest day: −4.5 °C, on 18 July 1970
- Heaviest rain in one day: 276.0 mm, on 3 February 1990
2.5 °C separate the warmest year of the series from the coldest. Between the hottest and the coldest day on record, the range reaches 50.0 °C.
Temperature trend over 1961–2025
The regression line of annual mean temperature changes by +0.25 °C per decade between 1961 and 2025, about +1.6 °C over the whole period. That is faster than the median of the 227 stations (+0.19 °C per decade), by 0.06 °C per decade: the station ranks 49 out of 227.
The last 24 months against the 1991–2020 normal
Over the last 24 months (October 2024 to September 2026), 12 months out of 15 were warmer than the 1991–2020 normal for the same month; the mean departure is +1.0 °C. The highest departure was in October 2025 (+2.5 °C); the lowest, in January 2025 (−0.4 °C). The last twelve months add up to 719 mm of rain, which is 66 % of the 1991–2020 annual normal (1093 mm).
| Month | Temperature | Departure from normal | Rain | Normal rain |
|---|---|---|---|---|
| October 2024 | 18.3 °C | 0.0 °C | 58 mm | 70 mm |
| November 2024 | 22.4 °C | +2.0 °C | – | 86 mm |
| December 2024 | 24.2 °C | +2.0 °C | 13 mm | 75 mm |
| January 2025 | 23.4 °C | −0.4 °C | 255 mm | 77 mm |
| February 2025 | 23.7 °C | +0.3 °C | 33 mm | 119 mm |
| March 2025 | 23.0 °C | +1.5 °C | 145 mm | 121 mm |
| April 2025 | 19.8 °C | +1.4 °C | 180 mm | 101 mm |
| May 2025 | 16.8 °C | +1.4 °C | 502 mm | 117 mm |
| June 2025 | 12.7 °C | −0.4 °C | 66 mm | 133 mm |
| July 2025 | 12.7 °C | +0.5 °C | 152 mm | 75 mm |
| August 2025 | 14.0 °C | +0.9 °C | 255 mm | 56 mm |
| September 2025 | 17.1 °C | +1.3 °C | 58 mm | 63 mm |
| October 2025 | 20.8 °C | +2.5 °C | 31 mm | 70 mm |
| November 2025 | 22.1 °C | +1.7 °C | 21 mm | 86 mm |
| December 2025 | 23.0 °C | +0.8 °C | 31 mm | 75 mm |
| January 2026 | – | – | 94 mm | 77 mm |
| February 2026 | – | – | 23 mm | 119 mm |
| March 2026 | – | – | 107 mm | 121 mm |
| April 2026 | – | – | 24 mm | 101 mm |
| May 2026 | – | – | 194 mm | 117 mm |
| June 2026 | – | – | 46 mm | 133 mm |
| July 2026 | – | – | 72 mm | 75 mm |
| August 2026 | – | – | 42 mm | 56 mm |
| September 2026 | – | – | 34 mm | 63 mm |
Data source and licence
Data source: Bureau of Meteorology (ACORN-SAT) and NOAA NCEI (GHCN-Daily) (dataset “ACORN-SAT v2 daily (homogenised) + GHCN-Daily”), licence CC BY 4.0; Public domain (NOAA NCEI). Last updated: 29 October 2026.
The data for Williamtown are shown as the source publishes them; this site does not correct them. A year is kept only if at least eleven months of measurements are available, and a normal is computed only with at least twenty years of data out of its thirty. Temperatures are rounded to 0.1 °C and rainfall to the millimetre. The station is one of 227 stations in Australia: the overview page lets you compare them.
Frequently asked questions
What is the annual mean temperature at Williamtown?
Over 1991–2020, the annual mean temperature at Williamtown is 18.1 °C. It was 17.4 °C over 1961–1990, a difference of +0.7 °C.
What is the warmest year ever measured at Williamtown?
Since records began in 1944, the warmest year at Williamtown is 2019, at 19.2 °C on average. The coldest is 1960 (16.7 °C).
Is the climate at Williamtown getting warmer?
Yes: at Williamtown, the annual mean temperature rises by 0.25 °C per decade between 1961 and 2025, +1.6 °C in total. 8 of the 10 warmest years in the series fall after 1999.
Towns near this station
Neighbouring stations