Tomatoes with dull (non shiny) skins

I've grown Gardeners Delight in grow bags in the greenhouse for several years.

In previous years I've had the occasional tomato with a dull (non shiny) skin. The colour is dull as well, not the bright coloured skin of a normal tomato.

This year I've used the same seed as last year. Quite a lot of the tomatoes are dull this year (about 25%).

Any ideas why this is happening this year?

Swaine

I suspect E G is right about the weather being a factor.

It seems counter-intuitive, but I think when you have a lot of cool/cloudy or damp weather, the roots and vascular tissue of plants can suffer, and plants can experience a "drought", even when there is plenty of water, because less water is reaching the leaves and fruits. I think this can happen even in a greenhouse because the plant health is not optimal, due to weather.

I see dull fruits on my tomatoes, including Gardener's Delight, when the plants are declining in health. I'm seeing that now, late in the season, and with too much rain.