We believe the pandemic not only accelerated some existing purchase intent within the recreational vehicle and marine markets these last 15 months, but we are equally convinced there has been, is and will be a meaningful expansion of interest and engagement in the outdoors that will benefit our business and industries for many years, even through when avoidable cyclical periods that have been and will be a part of the outdoor economy for decades.
With 10.1 million households having camped for the very first time in 2020 and another estimated 4.3 million households undergoing their own rookie camping experience as well in 2021, our team is helping to meet increased demand for our products and brands while delivering record financial performance.
In the third quarter, Winnebago Industries grew net sales to a record $960.7 million, representing a 139% growth year over year and an organic ex-Newmar growth of 53% over our pandemic fiscal third quarter in 2019.
As of April 2021, our RV fiscal year-to-date market share is now 12.5%, up 40 basis points from the same period last year.
Winnebago Industries top-line performance in the third quarter also represented 14% sequential growth over our fiscal 2021 second quarter.
Sales increased by 81.6% as compared to two years ago for third-quarter 2019, representing strong organic growth of our brands and also benefiting from the acquisition of Newmar.
Sales increased by 14% in Q3 as compared to Q2, representing the continued efforts by our supply chain and our team to generate increased output to meet the very strong demand that our dealers and end customers are exhibiting for our products.
This is also demonstrated by the record backlog related to dealer orders, up an additional 18.2% versus Q2.
Gross margins of 17.7% increased 130 points versus the 16.4% of third quarter two years ago, driven by cost savings initiatives, product mix and productivity improvements.
Gross margins declined modestly in Q3 compared to Q2; 17.7% in Q3, as compared to 18.6% in Q3 -- Q2, excuse me, driven by labor productivity impact from some of the supply chain inconsistencies, timing of investments in the business and higher material costs.
Margins of 17.7% in Q3 were well above our historical run rate and reflect primarily, the improvement in the motorhome segment.
Net income increased to $71.3 million in Q3, which is up 97% or almost double what was delivered two years ago.
Net income increased 3%, compared to the $69.1 million in Q2.
Reported diluted earnings per share of $2.05 in Q3 compares to a reported diluted earnings per share of $0.37 in the prior-year period and sequentially compares to a reported diluted earnings per share of $2.04 in Q2.
Adjusted diluted earnings per share of $2.16 in Q3 compares to $2.12 in Q2.
Diluted earnings per share was $1.14 Q3, two years ago.
Revenues for the towable segment were $555.7 million for the third quarter and increased 26.5% sequentially versus the second quarter, driven by elevated output and supported by strong consumer demand for our Grand Design and Winnebago-branded products.
Winnebago Industries' unit share of the North American towable market on a trailing three-month basis through April 2021, was 11.4%, reflecting an increase of 90 basis points over the same period last year.
Segment adjusted EBITDA was $80.1 million, up 28.5% sequentially or compared to the second quarter.
Adjusted EBITDA margin was a strong 14.4%, increasing from 14.2% in Q2, as continued leverage and pricing, combined with lower discounts and allowances, helped to offset rising costs driven by inflation.
Backlog increased to a record $1.5 billion, an increase of 17% versus the second quarter, reflecting continued strong consumer demand, combined with extremely low levels of dealer inventory.
In the third quarter, revenues for the motorhome segment were $385.3 million, up 1% sequentially compared to the second quarter.
Segment adjusted EBITDA was $37.5 million, compared to a loss of $10.8 million in the same period last year.
EBITDA in Q2 was $51 million.
EBITDA margins of 9.7% remained very strong relative to the 4% to 5% recorded historically, and is down from a record Q2 due to a different product mix, lower productivity due to the supply chain inconsistencies and also investments in the business, including the very successful dealer meeting held by the Newmar business.
The Newmar EBITDA margin of 9.7% was well ahead of EBITDA in Q3 of 2019 at 0.2%, reflecting the significant improvements from our cost savings, productivity and product mix.
Backlog in the motorhome segment increased to a record $2.2 billion, an increase of 323.3% over the prior year and an increase of 21.2% versus Q2 as dealers continue to experience significant reductions in inventories due to extremely high levels of consumer demand.
While we are experiencing inflationary pressures and remain conscious of competitive dynamics that may impact our net pricing equation, as well as continued supply chain inefficiencies caused by certain chassis or component constraints, we continue to expect to achieve a level of sustained profitability that is notably above the 4% to 5% EBITDA margin we've delivered in this segment historically.
Driven by consistent levels of gross debt, growing levels of cash and consistent growth in adjusted EBITDA, our leverage ratio or net debt to adjusted EBITDA, is now 0.5 times.
Our liquidity, including our currently untapped ABL, is just short of $600 million.
Cash flow from operations was $148 million in the first nine months of fiscal 2021, a decrease of $14.5 million from the same period last year.
On a quarterly basis, cash flow from operations was $81 million in Q3, which is an increase of $11.4 million versus the $69.6 million in Q2.
Our effective tax rate in our fiscal third quarter decreased to 22.8%, compared to 25.3% in the same period last year.
For the full year, we currently expect our tax rate to approximate 23% to 24%, excluding all discrete items from year-to-date results and those that may occur in the remainder of the year.
During the third quarter, we paid a dividend of $0.12 per share on May 19, 2021, and, and our Board of Directors just approved a quarterly cash dividend of $0.12 per share payable on June 30, 2021, to common stockholders of record at the close of business on June 16, 2021.
We joined over 12,000-plus global signatories, including several others in the outdoor recreation industry in supporting United Nation Global Compact's 10 principles and integrating these principles into our company's strategy.
In the immediate future over the next 12 to 18 months, we will add capacity in many ways, building new facilities, as well as reengineering existing business processes operational flow or building redesigns.
We believe industry wholesale shipments will grow approximately 50% annually in our 2021 fiscal year, and we are aligned with the RVIA forecast of approximately 34% more shipments for the industry for the full 2021 calendar year.

Summary:
In the third quarter, Winnebago Industries grew net sales to a record $960.7 million, representing a 139% growth year over year and an organic ex-Newmar growth of 53% over our pandemic fiscal third quarter in 2019.
Reported diluted earnings per share of $2.05 in Q3 compares to a reported diluted earnings per share of $0.37 in the prior-year period and sequentially compares to a reported diluted earnings per share of $2.04 in Q2.
Adjusted diluted earnings per share of $2.16 in Q3 compares to $2.12 in Q2.