With accent marks:
Гото́вь са́ни ле́том, а теле́гу зимо́й.
Get your sleigh ready in summer and your (horse-drawn) cart in winter.
This proverb reminds us to plan what we want to do and what we will need to do in advance so that any difficulties and unforeseen situations do not catch us by surprise.
There is almost the same proverb in English: "Repair your cart in December, in July your sledge remember".
Other Russian proverbs
When I eat I am deaf and mute.
You can't hide an awl in a bag.
You see your friends in the times of trouble.
Patience and labor will grind everything.
One head is good, but two ones are better.
You can't help grief with tears.
Where it is thin, it breaks.
Better to see once than hear a hundred times.