In most places it is best to wait until at least the end of June or into July when the bushes are completely dormant. Early pruning can, in some instances, result in new growth appearing in the next few weeks. These soft young shoots are very susceptible to cold winter weather and usually will not survive. This means the buds you have cut to are spent and will not re-shoot in spring. - Noelle
Winter is the right time to prune roses, although you might want to wait a month or two if you're in an area that gets frosts. Pruning is important to encourage new growth and flowers. Here's a how-to video:
My tip would be to ensure you have a good pair of gardening gloves and really sharp secateurs. You might also need a saw to remove the really old dark brown stems. - Isobel
Don't be too worried when pruning. Roses are really tough so you're not going to hurt the plant. The worst thing that can happen is that you just get a few less flowers next season. Remember to get rid of all the dead wood and make the cut on the new wood just above the buds on the stems - the buds are where the new shoots emerge.
I try to wipe my secateurs with warm soapy water after each use, then rub them with a bit of vegetable oil to keep them from rusting. I have one of these to sharpen the blades.
While winter is traditionally the time for pruning roses, I see Yates is encouraging rose owners to also prune in summer for another flush of blooms in autumn. - greygardener
When the roses have finished their original flush you can deadhead them by cutting the stems back as if you were going to cut it to put in a vase. This will act like a summer pruning and keep the bush in shape and bring on the next flush.
Always cut to an outward facing bud if possible. This will keep the centre of the plant open for air flow. I remember hearing the curator of Flemington Race Course saying that they did the pruning of their roses 65 days before the Melbourne Cup and their display is always magnificent.
I clean my secateurs by wiping them down with methylated spirits and then wiping them over with machine oil. If I happen to work on a plant with a problem I clean them and then move to the next, this way I don't spread the problem to any other plants.
To sharpen I use the mill file and then fine tune on a whetstone, this brings them up nearly razor sharp. - bergs
Most roses are pretty straightforward - reduce by up to 2/3rds in winter. Climbing roses not so much.
Climbers (and single blooming varieties, those that only bloom in spring) should generally be pruned after their main flowering. The way they are pruned will often depend on the variety so really worth keeping the label as it likely has variety-specific info.
Pruning a climbing rose requires a slightly different approach to clipping a shrub rose. For the first two years train the rose in the directions you would like it to go only removing damaged and diseased shoots or dead branches. You are not really concentrating on pruning for flower production at this stage.
From the third year prune main shoots to the desired form and shape. The side shoots need to be cut back by 2/3 or to a point where three or four buds are left.
You may want to keep the plant tidy by removing spent flowers; this can bring on new blooms. Remember though that some forms are only single bloomers and are highly regarded for their beautiful autumn and winter display of colourful rosehips, you’ll be losing this if you clip the old flowers off. - Adam_W