Recordings at Timaru's Richard Pearse Airport showed 108.6mm of rain fell in April, almost 70mm more than normal for the month, MetService meteorologist Lisa Murray said.
Federated Farmers National Arable Industry Group chairman Guy Wigley, who farms near Waimate, said recent wet weather was a double blow for farmers struggling to recover from a Canterbury-wide fire ban as a result of the Port Hills fires in February.
Mr Wigley said the fire ban was ''well meaning''.
''It [was] not because of a fire risk in the [wider] Canterbury area ... but because the Port Hills fire was tying up resources, so if a stubble fire had got out of control, it would have been hard to respond to that.''
The fire ban has since been lifted but stubble paddocks were now too wet to ignite, delaying the process of sowing more crops.
''It's had a huge impact on arable farmers,'' Mr Wigley said.
''In a normal season they would have resumed.
''It's gone on to create a real headache for arable farmers who have stubble and straw [which] is soaking wet. You can't burn it, you can't cultivate it.
''Burning it is an absolute crucial part of the arable rotation.''
Wet weather also affected crops, causing a lot of sprouting.
Mr Wigley said some farmers could be $100,000 worse off because of the delays.
He said wheat crops established at the beginning of April would yield 10% more than a crop established a month later; and there was no chance of farmers making up for lost time.
''Even if farmers do get their crops harvested they will already take a yield penalty.''
Mr Wigley was optimistic he would get three-quarters of his plantings done by the end of this month.
''That leaves me with a quarter to be planted in spring, which is not plan A,'' he said.
''I usually have it all done by the end of April.''
Wet weather has not been bad news for all farmers. Dairy, sheep and beef farmers were getting good grass growth, Federated Farmers South Canterbury provincial president Mark Adams said.
But, for arable farmers, next year's yield would be jeopardised.
There was no quick-fix, he said.
The only way around it was sunshine.
And, with farming, there was always going to be a catch-22.
''When arable farmers are doing well, we are very dry and when it's wet, dairy is doing very well,'' Mr Adams said.
''That's the tension that we live with.''
And, last month was no exception.
Federated Farmers South Canterbury Provincial Dairy chairman Ryan O'Sullivan said up until now conditions were ''very dry'', particularly for dryland farmers.
''The irrigated farmers were still OK,'' he said.
However, April's rainfall had made a big difference to unirrigated winter feed crops, which were relied on over the coming months.
The rain also meant some farmers could save money in terms of electricity and workload, he said.
-By Alexia Johnston