Climate and Average Weather Year Round in Bornholm Denmark

In Bornholm, the summers are comfortable, windy, and partly cloudy and the winters are long, very cold, snowy, extremely windy, and mostly cloudy. Over the course of the year, the temperature typically varies from 30°F to 70°F and is rarely below 18°F or above 78°F.

Based on the tourism score, the best time of year to visit Bornholm for warm-weather activities is from late June to late August.

The warm season lasts for 3.0 months, from June 11 to September 11, with an average daily high temperature above 63°F. The hottest month of the year in Bornholm is August, with an average high of 68°F and low of 57°F.

The cold season lasts for 4.0 months, from November 28 to March 27, with an average daily high temperature below 43°F. The coldest month of the year in Bornholm is February, with an average low of 30°F and high of 37°F.

In Bornholm, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year in Bornholm begins around April 17 and lasts for 6.0 months, ending around October 15.

The clearest month of the year in Bornholm is July, during which on average the sky is clear, mostly clear, or partly cloudy 57% of the time.

The cloudier part of the year begins around October 15 and lasts for 6.0 months, ending around April 17.

The cloudiest month of the year in Bornholm is January, during which on average the sky is overcast or mostly cloudy 69% of the time.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Bornholm varies throughout the year.

The wetter season lasts 7.8 months, from June 22 to February 15, with a greater than 25% chance of a given day being a wet day. The month with the most wet days in Bornholm is November, with an average of 9.2 days with at least 0.04 inches of precipitation.

The drier season lasts 4.2 months, from February 15 to June 22. The month with the fewest wet days in Bornholm is April, with an average of 5.7 days with at least 0.04 inches of precipitation.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. The month with the most days of rain alone in Bornholm is November, with an average of 8.9 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 31% on November 12.

Rainfall

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Bornholm experiences some seasonal variation in monthly rainfall.

Rain falls throughout the year in Bornholm. The month with the most rain in Bornholm is July, with an average rainfall of 2.0 inches.

The month with the least rain in Bornholm is February, with an average rainfall of 1.1 inches.

Snowfall

As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Bornholm experiences some seasonal variation in monthly snowfall.

The snowy period of the year lasts for 3.1 months, from December 9 to March 13, with a sliding 31-day snowfall of at least 1.0 inches. The month with the most snow in Bornholm is February, with an average snowfall of 1.9 inches.

The snowless period of the year lasts for 8.9 months, from March 13 to December 9. The least snow falls around August 2, with an average total accumulation of 0.0 inches.

The length of the day in Bornholm varies extremely over the course of the year. In 2024, the shortest day is December 21, with 7 hours, 8 minutes of daylight; the longest day is June 20, with 17 hours, 24 minutes of daylight.

The earliest sunrise is at 4:19 AM on June 17, and the latest sunrise is 4 hours, 7 minutes later at 8:26 AM on December 28. The earliest sunset is at 3:30 PM on December 13, and the latest sunset is 6 hours, 14 minutes later at 9:44 PM on June 24.

Daylight saving time (DST) is observed in Bornholm during 2024, starting in the spring on March 31, lasting 6.9 months, and ending in the fall on October 27.

The figure below presents a compact representation of key lunar data for 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases.

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

The perceived humidity level in Bornholm, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, staying within 3% of 3% throughout.

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in Bornholm experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 6.1 months, from September 16 to March 20, with average wind speeds of more than 15.6 miles per hour. The windiest month of the year in Bornholm is January, with an average hourly wind speed of 19.1 miles per hour.

The calmer time of year lasts for 5.9 months, from March 20 to September 16. The calmest month of the year in Bornholm is May, with an average hourly wind speed of 12.1 miles per hour.

The predominant average hourly wind direction in Bornholm varies throughout the year.

The wind is most often from the east for 2.4 weeks, from April 21 to May 8, with a peak percentage of 36% on May 4. The wind is most often from the west for 11 months, from May 8 to April 21, with a peak percentage of 45% on January 1.

Bornholm is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.

The average water temperature experiences significant seasonal variation over the course of the year.

The time of year with warmer water lasts for 2.7 months, from June 28 to September 20, with an average temperature above 59°F. The month of the year in Bornholm with the warmest water is August, with an average temperature of 64°F.

The time of year with cooler water lasts for 4.2 months, from December 19 to April 25, with an average temperature below 42°F. The month of the year in Bornholm with the coolest water is February, with an average temperature of 37°F.

To characterize how pleasant the weather is in Bornholm throughout the year, we compute two travel scores.

The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit Bornholm for general outdoor tourist activities is from late June to late August, with a peak score in the third week of July.

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Bornholm for hot-weather activities is from mid July to mid August, with a peak score in the last week of July.

Methodology

For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.

Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.

Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.

Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.

Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

The growing season in Bornholm typically lasts for 6.6 months (200 days), from around April 18 to around November 5, rarely starting before April 1 or after May 4, and rarely ending before October 13 or after December 5.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

Based on growing degree days alone, the first spring blooms in Bornholm should appear around May 22, only rarely appearing before May 11 or after June 5.

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy experiences extreme seasonal variation over the course of the year.

The brighter period of the year lasts for 3.2 months, from May 3 to August 10, with an average daily incident shortwave energy per square meter above 5.4 kWh. The brightest month of the year in Bornholm is June, with an average of 6.6 kWh.

The darker period of the year lasts for 4.2 months, from October 19 to February 25, with an average daily incident shortwave energy per square meter below 1.6 kWh. The darkest month of the year in Bornholm is December, with an average of 0.4 kWh.

For the purposes of this report, the geographical coordinates of Bornholm are 55.126 deg latitude, 14.914 deg longitude, and 0 ft elevation.

The topography within 2 miles of Bornholm is essentially flat, with a maximum elevation change of 0 feet and an average elevation above sea level of 0 feet. Within 10 miles is also essentially flat (0 feet). Within 50 miles is also essentially flat (0 feet).

The area within 2 miles of Bornholm is covered by trees (71%) and cropland (28%), within 10 miles by cropland (51%) and water (32%), and within 50 miles by water (93%).