The change is mainly in us. (Ice out)

March 31.

I see through the window that it is a very fine day, the first really warm one. I do not know the whole till I come out at 3 P. M. and walk to the Cliffs. 

The slight haze of yesterday has become very thick, with a southwest wind, concealing the mountains. I can see it in the air within two or three rods, as I look against the bushes. 

The fuzzy gnats are in the air, and bluebirds, whose warble is thawed out. I am uncomfortably warm, gradually unbutton both my coats, and wish that I had left the outside one at home. 

I go listening for the croak of the first frog, or peep of a hylodes.

It is suddenly warm, and this amelioration of the weather is incomparably the most important fact in this vicinity. It is incredible what a revolution in our feelings and in the aspect of nature this warmer air alone has produced. 

Yesterday the earth was simple to barrenness, and dead, —bound out. Out-of-doors there was nothing but the wind and the withered grass and the cold though sparkling blue water, and you were driven in upon yourself. 

Now you would think that there was a sudden awakening in the very crust of the earth, as if flowers were expanding and leaves putting forth; but not so.

I listen in vain to hear a frog or a new bird as yet; only the frozen ground is melting a little deeper, and the water is trickling down the hills in some places. 

No, the change is mainly in us. We feel as if we had obtained a new lease of life. 

Some juniper (repens) berries are blue now. 

Looking from the Cliffs I see that Walden is open to-day first.

H. D. Thoreau, Journal, March 31, 1855

Ice-out on Walden. See March 20, 1853 ("It is glorious to behold the life and joy of this ribbon of water sparkling in the sun. The wind ... raises a myriad brilliant sparkles on the bare face of the pond, an expression of glee, of youth, of spring, as if it spoke the joy of the fishes within it and of the sands on its shore. It is the contrast between life and death. There is the difference between winter and spring. The bared face of the pond sparkles with joy."); March 14, 1860 ("No sooner has the ice of Walden melted than the wind begins to play in dark ripples over the surface of the virgin water. Ice dissolved is the next moment as perfect water as if melted a million years.")

In 1845 Walden was first completely open on the 1st of April;

in '46, the 25th of March; 

in '47, the 8th of April; 

in '51, the 28th of March;

 in '52, the 18th of April; 

in '53, the 23rd of March; 

in '54, about the 7th of April. ~ Walden.

See also A Book of the Seasons, by Henry Thoreau, Ice-Out