Summer ROOF improvements, it makes sense.
Summer is the time to improve or repair your roof. Whether it is a pitched, flat, tiled etc roof, the benefits of doing any preventive maintenance far out weigh the reasons for NOT repairing your roof.
Consider these points:
If any tiles have lifted from your roof and the roofer needed to lift a couple more to re-align everything, then it is best to schedule this in times when we are more likely to have dry weather.
Replacing tiles or repairing roofs in the rain… just simply is not a good idea. Raining can penetrate the loft and cause all sorts of damage.
If you have workmen moving around through your home to access the loft area of your roof, it is best done when the streets are not wet with rain.