Temperatures in May
It's cool to moderate in May in Portland with an average temperature of 18°C. Temperatures this month range from a low of 13°C to a high of 24°C. At night, you can expect temperatures between 5°C and 12°C.
Max and Min Temperatures per Day
This chart shows the daily maximum and minimum temperatures in degrees Celsius for Portland in May. The red line indicates the max temperatures, and the blue line shows the minimums.
Start of May
The month of May starts in Portland with cool temperatures, averaging around 16°C during the day and nights close to 7°C. A few showers might pop up in the first days of the month, but the weather remains mostly sunny and dry.
Mid-May
By mid-May, the average daytime temperature rises to around 19°C, with nights close to 9°C. There might be a few showers during this period, but plenty of dry days with sunshine too.
End of May
By the end of May, the average daytime temperature in Portland will be around 21°C, with nights close to 11°C. A shower might show up, but overall the weather will be dry and sunny.
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Water temperature
The water temperature at Portland is 12°C this month. This is too cold to swim without protective gear.
Precipitation in May
In May, there is an average of 73 mm of precipitation, spread over 8 days. Of the total precipitation, about 0,1 cm falls as snow in May. The wind speed is around 4 Bft, mostly coming from the South.
The average precipitation chance is 26% per day this month. Though it seems pretty low, the weather’s variable. Some days have higher and others lower precipitation chances, which lowers the average.
Precipitation Chance
This chart shows the daily precipitation chance (in percentages) in May for Portland. 0% means it never rained on that day in the past 10 years, and 100% means it rained every day. All values in between represent the average chance of precipitation on that day.
Portland in May |
London | ||
|---|---|---|---|
 Average Temperature |
18°C | 18°C | |
 High Temp |
24°C | 21°C | |
| Low Temp |
13°C | 15°C | |
 Total Precipitation |
73 mm | 46 mm | |
| Rainy Days |
8 days | 8 days | |
 Total Snowfall |
0,1 cm | 0 cm | |
| Snowy Days |
1 day | 0 days | |
April
UV index
The UV index is a maximum of 6 this month. That's a moderate to high value on the intensity scale of 1 to 11. Unprotected skin can burn within 15-25 minutes.
Is May a good time to visit Portland?
Want nice weather? Then May is a great time to be in Portland. You’ll have pleasant temperatures and not too much rain this month.
Temperature records for Portland in May
With 34°C, Portland hit the highest temperature in the last 10 years in May 2017. The lowest daytime temperature in this month was 6°C in 2017. The extreme night temperatures ranged from a low of -2°C to a high of 19°C.
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Daily Temperature in May in Portland
This chart shows the average daily temperatures, both day and night, for each day in May in Portland, measured in degrees Celsius. The red line represents the maximum temperatures, while the blue line shows the minimums. The days of the month are displayed at the bottom of the chart. The data, based on historical observations, gives an overview of the average daily temperatures during this month.
Daily Precipitation in May in Portland
The chart below shows the average daily precipitation in May for Portland, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail. The days of the month are shown at the bottom of the chart.
A low average precipitation means that the chance of rain on that day is usually small, while a higher average suggests that rain is more likely. But it’s still an average, so each day can be different. Based on historical weather data for May, you can expect around 8 days of rain in Portland.
Daily Snowfall in May in Portland
This chart shows the average daily snowfall in May in Portland, measured in centimetres. The bottom of the chart shows the days of the month. The data is based on historical measurements and gives an idea of the average snowfall in May.
Daily UV Index in May in Portland
This chart shows the average daily UV index in May in Portland, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.
Temperature in May in Portland Over the Years
This chart shows the average temperature in May in Portland, measured in degrees Celsius, over the past years.
Total Precipitation in May in Portland Over the Years
This chart shows the average precipitation in May in Portland, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail.
Snowfall in May in Portland per year
This chart shows the average snowfall in May in Portland, measured in centimetres, over the past years.
Daily climate in May for Portland
Click on a specific day in May for detailed info on the typical weather on that day in Portland. Check out the historical temperatures and precipitation over the past 10 years on this day.
Weather experiences in May in Portland
Have you been to Portland in May?
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Average Weather in Portland by Month
Click on a month below to see detailed weather info for Portland. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.
