Weather in Cph

"According to the weather forecast today it's rainy, but the sun doesn't know it and it keeps shining."

The weather in Denmark deserves a special chapter. It's like having a child: you can't really predict how it will be and if your expectations are too high, you'll be inevitably disappointed!
In brief, you get about three days a year of real summertime (<28 degrees) and long, dark winters, surprisingly not as cold as you may expect.

Independently from the season, the most crucial element is the wind, whether it blows or it doesn't.
Copenhagen is frequently windy and clouds pass over it at an incredible speed. Wind will affect indirectly or directly the amount of daylight, the heat index, therefore the perceived temperature, the quality and duration of precipitations, finally whether you'll be able to enjoy your bike ride or struggle like mad.

The wind doesn't necessarily means bad weather, although it is mostly associated with it. It simply means rapid weather changes. You can experience within the same day what feels like four seasons.
The day may start cloudy, dark and chilly, then the sun might shine and be surprisingly hot, finally some rain in the evening might appear and then freezing air will catch you at night.
This is why trying to predict the weather in Denmark is hopeless and the weather forecast is useless. The websites predict the weather two hours in advance, since to say what's going to be in four might be too difficult!

The diurnal temperature variation is very extreme in Denmark all year round. As long as the sun shines temperatures are bearable, as soon as the sun goes down (even if the daylight is still on), they are not. Temperatures will decrease very rapidly when the sun is not shining and/or the wind is blowing, both in winter and summertime. Always bring a jacket ... no matter the season!

If you have people deciding to visit you, here it is what they can expect:
April - it is really the first month when you could decide to visit Denmark. You'll still find chilly temperatures, but at least the amount of daylight will be long enough to enjoy a full day.
May - the blooming month! Finally temperatures will rise and you'll be able to get rid off hats, gloves and scarves. The daylight will be very long. You'll still need a nice jacket if the sun is not shining and when the evenings come.
June - the first week of this month is probably the best over the year. It might get actually hot during the day and be nice and cool in the evenings.
July-August - they might be rainy, but overall quite nice. In July most of the danes leave on holidays and the city will appear quite dead.
September - it is great for the first ten days, then it is suddenly fall.
October-March - don't bother visiting Denmark. The amount of daylight is suddenly minimal and temperatures are often around zero. The cold is surprisingly easy to face with a nice coat, a hat and gloves since, thanks to not extreme humidity, does not penetrate your bones. It might snow, but usually it doesn't stick nor last. Careful on a windy day! The city atmosphere and the people spirits can be alright until Christmas, then depression kicks in.

If you still believe in the forecast ...
Danmark Meteorologisk Institut