May weather forecastPerth, Australia

May
Weather in May
May marks the further continuation of cooler weather in Perth, where autumn transitions into the early phase of winter. The rainfall during this month amplifies to a significant 90mm (3.54"), marking the onset of wetter conditions in the city. It's a period when coats and jackets begin to surface in public. With the lowering temperatures, the days start getting shorter, gradually reducing daylight hours. Despite the occasional rain showers, the recurring sun-filled intervals enliven the city, making May a month of contrasts.Temperature
A moderate decline in average high-temperatures is noted in Perth in May, moving from a moderately hot 25.9°C (78.6°F) in April to a pleasant 22.3°C (72.1°F). Perth throughout May, experiences an average nighttime temperature of 10.5°C (50.9°F).Humidity
In May, the average relative humidity in Perth is 50%.Rainfall
In May, the rain falls for 11.1 days. Throughout May, 90mm (3.54") of precipitation is accumulated. In Perth, Australia, during the entire year, the rain falls for 108.4 days and collects up to 725mm (28.54") of precipitation.Sea temperature
In May, the average sea temperature is 22.3°C (72.1°F).Note: Individual preferences to cold, influenced by conditions such as sunshine, wind, and surrounding temperature, play a part in the comfort of swimming in 22.3°C (72.1°F) waters. (As an aside, Olympic swimming standards dictate water temperatures from 25°C (77°F) to 28°C (82.4°F).)
Daylight
In May, the average length of the day in Perth is 10h and 30min.On the first day of the month, sunrise is at 6:48 am and sunset at 5:38 pm. On the last day of May, in Perth, sunrise is at 7:08 am and sunset at 5:20 pm AWST.
Sunshine
In Perth, the average sunshine in May is 6.9h.UV index
The average daily maximum UV index in May is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for average individuals.Note: The UV index of 4 during May translates into the following guidance:
Act with care - The need to guard against sun damage is communicated. The intensity of the Sun's UV radiation during midday suggests reducing time spent outdoors. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation. Take warning! Reflective sand and water surfaces intensify the Sun's UV rays.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in May
Perth, Australia
- Average high temperature in May: 22.3°C
The warmest month (with the highest average high temperature) is February (31.7°C).
The month with the lowest average high temperature is July (18.4°C).
- Average low temperature in May: 10.5°C
The month with the highest average low temperature is February (18.4°C).
The coldest month (with the lowest average low temperature) is July (7.7°C).
Average humidity in May
Perth, Australia
- Average humidity in May: 50%
The month with the highest relative humidity is July (57%).
The month with the lowest relative humidity is February (38%).
Average rainfall in May
Perth, Australia
- Average rainfall in May: 90.2mm
The wettest month (with the highest rainfall) is July (144.7mm).
The driest month (with the least rainfall) is February (8.8mm).
Average rainfall days in May
Perth, Australia
- Average rainfall days in May: 11.1 days
The month with the highest number of rainy days is July (16.9 days).
The month with the least rainy days is February (2.1 days).
Average sea temperature in May
Perth, Australia
- Average sea temperature in May: 22.3°C
The best month for swimming (with the highest average sea temperature) is March (23.4°C).
The coldest months (with the lowest average sea temperature) are September and October (19°C).
Average daylight in May /
Average sunshine in May
Perth, Australia
- Average daylight in May: 10h and 30min
The month with the longest days is December (Average daylight: 14h and 12min).
The month with the shortest days is June (Average daylight: 10h and 6min).
- Average sunshine in May: 6h and 54min
The months with the most sunshine are January and December (Average sunshine: 11h and 30min).
The month with the least sunshine is June (Average sunshine: 5h and 54min).
Average UV index in May
Perth, Australia
- Average UV index in May: 4
The months with the highest UV index are January and December (UV index 12).
The months with the lowest UV index are June and July (UV index 3).








