Carlisle saw off the challenge of Colchester thanks to Paul Thirlwell's first goal of the season.
Rory Loy twice went close for the hosts when first his shot forced a good save from Ben Williams and then his close-range header was deflected wide.
The Cumbrians took the lead after neat approach play from Jon-Paul McGovern and Lee Miller was finished off neatly by Thirlwell.
Ian Henderson came close to levelling for the U's but his shot was blocked.
VIEWS FROM THE DRESSING ROOM
Carlisle United manager Greg Abbott told BBC Radio Cumbria:
"It is a testimony to both teams, the way they have tried to play.
"It is not just the rain, the wind is the key, the rain is OK, the wind is horrendous.
"It was going to be tight, it was going to be edgy, games and points are hard to win and hard to come by in this league."
Colchester United manager John Ward told BBC Essex:
"I don't think, in the last 30 yards, our passing was as good as I wanted it to be to provide those opportunities for us.
"We got there more times but we didn't deliver that final cross or that shot or that bit of work to upset their goalkeeper. He had relatively routine afternoon.
"We passed it better in the second period but didn't get that right touch in the box. For a game that was dominated by the conditions there were very few goalmouth opportunities."