Thoughts turn to autumn as nights draw in

The pink-barred sallow moth emerges in September.
The pink-barred sallow moth emerges in September.

According to folklore, summer ends next Monday. St Matthew’s Day brings cool, unsettled weather that drives honeybees into their hives. But last week, in a cruel twist, the weather gods banished summer overnight.

Yet in the middle of the day, when the sun is warmest, it’s still possible to spot butterflies feeding on autumn-flowering plants such as sedum, aster, ivy, valerian and michaelmas daisy.

Peacocks and small tortoiseshells overwinter as adults, so they need to feed up before the time comes to hibernate. Look out for red admirals — they’re partial to over-ripe fruit such as windfall plums. No windfalls? No problem. That mushy banana languishing in the fruit bowl will be a big attraction for these handsome butterflies.

Last week we were asked to count migrant moths, because southerly winds bring glamorous rarities in September. However some resident species are emerging now, and they’re not all brown or grey. Some, like the pink-barred sallow, are coloured to blend with autumn leaves. If you live near a marshy spot or damp woodland, you could find this pretty moth in your garden.

All moths are fascinating, and attracting them isn’t too difficult. Simply leave a kitchen or porch light on and see what arrives. Or go out with a torch during the two hours after sunset — you’ll be amazed at what you find feeding on the flowers in your garden.

If you’d like to treat those moths, try this. Gently simmer some brown ale, black treacle, and brown sugar until they blend, then allow the potion to cool before dabbing it onto a fencepost.

Weather watch

“September blow soft, till the fruit’s in the loft.” Fruit trees have made good growth this year and apples are looking particularly fine. But September’s strong winds always threaten to strip fruit from branches before it is ready.

Autumnal thoughts are unavoidable as the nights draw in. As we get closer to the autumn equinox — it’s on September 23 at 9.20am — the hours of daylight decrease at a rate of four minutes each day.

Seafarers used to think that the autumn equinox brought gales, a belief that can be traced back to Roman times. Now we know that the remnants of Atlantic hurricanes drive September’s storms, and these can occur at any time in the month.

So far the hurricane season has been quieter than usual because high-level winds over the Atlantic have disrupted their formation. This is just one effect of the powerful El Nino developing in the Pacific — the unusually warm seas there are feeding tropical storms and speeding the winds high up in the atmosphere.

An El Nino event like this, which is strong enough to disrupt the world’s weather patterns, only happens every 10 to 15 years. The World Meteorological Organisation expects the current one to be the most powerful since 1997-98.

El Nino will probably reach its peak in late December. Could this affect Britain’s weather? Well, if the winter of 97-98 is any guide there will be fewer autumn storms, but a very cold new year with freezing spells continuing into April.