Great Lakes - Daily Precipitation for Last Month in Millimeters

The US Army Corps of Engineers collects and disseminates this daily precipitation data for the Great Lakes. All data are provisional, may contain missing observations, and are subject to change. Data are calculated from the best available US and Canadian observations at the time of posting. All precipitation data are preliminary. Precipitation data are stored and displayed in millimeters.

Month to Date Average (MTD AVG) Calculation: Long Term Average (LTA) Precipitation for the Month ÷ Total Number of Days in the Month × Day of the Month to Date
Percent of Month to Date Average (% of MTD AVG) Calculation: Accumulated Precipitation for the Month ÷ (Long Term Average (LTA) Precipitation for the Month ÷ Total Number of Days in the Month × Day of the Month to Date) × 100
Long Term Average (LTA), Maximum (MAX), and Minimum (MIN) precipitation data for the month are provided for historical reference.
Period of Record - 1900-2022

NOTICE: All data contained herein is preliminary in nature and therefore subject to change. The data is for general information purposes ONLY and SHALL NOT be used in technical applications such as, but not limited to, studies or designs. All critical data should be obtained from and verified by the United States Army Corps of Engineers, Detroit District, Engineering and Construction Division, Hydraulics and Hydrology Branch, 477 Michigan Ave., Detroit, MI 48226. The United States of America assumes no liability for the completeness or accuracy of the data contained herein and any use of such data inconsistent with this disclaimer shall be solely at the risk of the user.