Weather in Nelson went from one extreme to the other in May.

May brings ‘extremely variable weather’ in Nelson area

A ferocious storm late in the month helped make May the wettest month on record since 1990.

A ferocious storm late in the month helped make May the wettest month on record since 1990.

During the late afternoon of May 21, a strong cold front which produced a few thundershowers and strong gusty winds hit the region. A deep upper low pressure followed with heavy rain bringing the most 24-hour rainfall ever during May.

The 2-day rainfall of 82.4 millimetres ending the evening of May 22 accounted for 74 per cent of the month’s total rainfall, says Ron Lakeman of the Southeast Fire Centre.

The total amount of precipitation during the month was 163% of normal.

The weather forecaster points to the strong winds accompanying the storm that reached speeds of 57 km per hour with gusts of 83 km per hour. Wind speeds in May were 120 per cent of normal.

Lakeman describes May as “another month of extremely variable weather.”

The mean monthly temperature averaged out to be 1.3 degrees warmer than normal despite setting a record for a cold temperature.

“The month began with a dry northerly flow and clear skies combining for a record cold temperature of -4.7 degrees during the early morning of the first,” he said. “This record daily minimum temperature is also the new record minimum temperature during the month of May, the previous was -2.5 degrees from 2002 and 2012.”

Conditions quickly reversed with an upper ridge of high pressure providing dry, generally sunny and unseasonably warm conditions the following 11 days.  Record daily maximum temperatures of 29.4, 32.1 and 30.8 degrees were set on the 8th, 10th and 11th respectively.

After the big storm mid-month, a series of smaller Pacific disturbances spread frequent but lighter showers and thundershowers across the area during the remainder of the month.