2021 monsoon season ends as one of the wettest on record, but drier than usual winter is expected

PHOENIX - 2021's monsoon season. which officially ends on Sept. 30, was a record-setter in terms of rainfall.

From wind and lightning to several inches of rain, 2021's monsoon season was one to remember, and it was a marked departure from 2020's monsoon season, which was one of the driest.

"It was the best we’ve had in awhile," said Marvin Percha, a meteorologist with the National Weather Service. "I know a lot of people focus on Sky Harbor, 4.2 inches. It’s the 26th wettest for Sky Harbor, but we have what we call the Phoenix Rainfall Index. This is something that’s been tabulated since 1990, and it’s an average of rain gauges around the metro, and it was 5.82, which is the second highest on record."

Arizona relies on the monsoon season and the winter for rain, and 2020's dry monsoon and winter seasons meant SRP's reservoirs dropped significantly. This year's rain, however, helped maintain water levels.

"Because the monsoon season was so productive, at the end of the monsoon season right now, we're sitting almost at the same level. I believe we’re at 71%, so not only did the monsoon deliver to our reservoirs all the water that we used, but they kept us full," said SRP Watershed Management Manager Charlie Ester. "If we would have had another dry monsoon, like last year, our reservoir's storage would be closer to 50%."

National Weather Service Meteorologist Jaret Rogers said normally, the summer monsoons are not enough to really help with the drought and longer-term water supply, since it happened during such a short time period, but 2021 was different.

"We've had such a wet monsoon that actually, we've seen a lot of drought improvement across the state. We had 86% of Arizona in the most significant drought categories, D3 and D4, extreme and exceptional drought. That is down to 14% now," said Rogers.

Rogers, however, said there will be plenty of cooler and drier days ahead for Arizona.

"We are expecting it to be a drier winter ahead, so we're not going to get as much rain as normal," said Rogers.

Rogers said we could still see a few rainy days here or there in the coming weeks, but that once Arizona hits late fall and winter, the state will really start to dry out. This is why Rogers said it is so important to have had an active monsoon season.

"We have La Nina developing, so we're more confident that we're not gonna get as much rain as normal," said Rogers. "Heading into winter, it's good we had such a wet monsoon. That definitely gave us more of a cushion if we do end up having a drier winter overall."

"If things work out to be a little bit more normal, at least we won’t be going into next year with quite a deficit we had this year," said Percha.