Frost forms on windows.

February 1 

2p.m.  - 5°. A cold day. 

Two or three inches of dry snow last night. Grows colder apace toward night. Frost forms on windows.

H. D. Thoreau, Journal, February 1, 1860

Frost forms on windows. See December 28, 1859 ("In the morning the windows are like ground glass (covered with frost), and we cannot see out."); January 4, 1856 ("It is snapping cold this night (10 P. M.). I see the frost on the windows sparkle as I go through the passageway with a light ")'; February 5, 1855 ("It was quite cold last evening, and I saw the scuttle window reflecting the lamp from a myriad brilliant points when I went up to bed."); February 17, 1860 ("Grows colder yet at evening, and frost forms on the windows.")