Midsummer, the very much beloved weekend is in Sweden the Midsummer Eve and the Midsummer Day.
The Midsummer Day is celebrated according to a law from 1952 on the Saturday which comes in sometime between June 20-26.

The Midsummer (Midsommar), the longest day of the summer, where, in the North of Sweden, the sun does not set all night long.
The holiday always begins on a Friday, Midsummer Eve. After the (midsommarstång) pole is covered with flowers and greenery and erected, the community dances around it while singing traditional Swedish songs.
Traditional Swedish foods and drinks are served, such as sill (marinated herring), Swedish meatballs, chicken on the grill, fresh potatoes with dill, fresh strawberries with whipped cream for dessert, and any other light summer foods.

 A Swedish tradition is for the girls; pick seven different flowers and put them under the pillow when you go to sleep in the Midsummer night. The man you will dream about is the man you are going to be married to!

MIDSUMMER
"After the May time and after the June time
Rare with blossoms and perfume sweet,
Cometh the round world's royal noon time,
The red midsummer of blazing heat,
When the sun, like an eye that never closes,
Bends on the earth its fervid gaze,
And the winds are still, and the crimson roses
Droop and wither and die in its rays.

Unto my heart has come this season,
O, my lady, my worshiped one,
When, over the stars of Pride and Reason,
Sails Love's cloudless, noonday sun.
Like a great red ball in my bosom burning
With fires that nothing can quench or tame,
It glows till my heart itself seems turning
Into a liquid lake of flame.

The hopes half shy and the sighs all tender,
The dreams and fears of an earlier day,
Under the noontide's royal splendor,
Droop like roses, and wither away.
From the hills of Doubt no winds are blowing,
From the isles of Pain no breeze is sent, -
Only the sun in a white heat glowing
Over an ocean of great content.

Sink, O my soul, in this golden glory!
Die, O my heart, in thy rapture-swoon!
For the Autumn must come with its mournful story.
And Love's midsummer will fade too soon."

Ella Wheeler Wilcox (1850-1919)

Visit Helena´s wonderful page about Midsummer, it´s great!