Country Overview For Finland
The climate in Finland is typically cold temperate; potentially subarctic but comparatively mild because of moderating influence of the North Atlantic Current, Baltic Sea, and more than 60,000 lakes. The terrain: mostly low, flat to rolling plains interspersed with lakes and low hills. For Helsinki in January the daily average maximum temperatures is 0°C with the average minimum -4°C, while in June the average maximum is 16°C with a minimum of 11°C. The wettest month for Helsinki is October with an average of 73.3mm of precipitation falling while the driest month is May with 30.3mm falling.
HISTORICAL MONTHLY AVERAGES FOR MAY
The information presented below gives detailed historical monthly average weather conditions along with exceptional weather occurrences. To maintain relevance to current weather trends the displayed information has been calculated using data collected over the past two decades. The climate profile is taken from closest available data source to Vantaa.
Throughout the month of May daytime temperatures will generally reach highs of around 15°C that's about 60°F. At night the average minimum temperature drops down to around 4°C, that's 40°F.
In recent times the highest recorded temperature in May has been 29°C that's 84°F, with the lowest recorded temperature -5°C, about 22°F.
The average daily relative humidity for May is around 61%.
The Heat Index is a measure of how hot it feels when relative humidity is added to actual air temperature. From this a comfort level is calculated providing categories on how heat conditions might adversely affect someone.
Comfort Levels: Given average maximum temperatures and humidity levels generally you should not anticipate any discomfort from heat (see heat index for more information).
The average monthly amount of precipitation has been recorded at around 33 mm, that's 1 inches. Throughout the month you can expect to see rain or drizzle falling on 14 days of the month, with snow falling on 1 days.
Estimated Hours of Sunshine per Day
We calculate sunshine hours per day using our past forecast data. For May expect the sun to shine for an average of 10 hours per day. This represents the average number of hours in the daytime that the sun is visible and not obscured by cloud e.g. the average number of hours the sun is actually out and shining. Note we calculate hours of sunshine per day using our past forecast data, not observation data, thus it is an estimate and not actual.
The average daily wind speed in May has been around 13 km/h, that’s the equivalent to about 8 mph, or 7 knots. In recent years the maximum sustained wind speed has reached 46 km/h, that’s the equivalent of around 29 mph, or 25 knots.
On average the month of May is affected by foggy conditions on 3 days.
SWIMMING AND WATER TEMPERATURE
The temperature of water an individual will feel comfortable in is very much personal preference. What feels unbearably cold to one person for a swim might be fine for another. We have created our own Swimming Water Temperature Index offering a guide to water temperature and comfort levels for swimming;
In May, for the nearest coastal location, the temperature of the sea averages around 5°C, that's 41° Fahrenheit. Our index indicates for swimming this is considered very cold and even the most hardy among us would be foolhardy to venture in for a swim and risk hypothermia if exposed for any more than a few minutes.
YEARLY TRENDS: WEATHER AVERAGES & EXTREMES
The following charts show yearly weather trends with information on monthly weather averages and extremes.
The chart below plots the average high and low temperature for each month of the year. It also shows the maximum and minimum recorded temperatures.
The chart below plots the average monthly precipitation amount.
The chart below plots the average number of days in any month that you can expect to see rain falling.
The chart below plots the average number of days in any month that you can expect to see snow falling.
The chart below plots the average daily wind speed you can expect for any month. It also shows the maximum recorded sustained wind speed for each month.