Rainfall data for Portland

Accessing the rainfall data

There are multiple ways to view the data. The data table provides an overview of all rain gauges. The interactive map enables you to click on a site and view rainfall totals, charts, and other relevant details.

Environmental Data Portal welcome page

Latest rainfall data table for all rain gauges

Map of rain gauge locations

For help navigating the portal and exploring additional features, charts, and tools, view the guide or watch the video tutorial.

Getting Started Guide

About the rainfall data and portal

Rainfall data is collected by Environmental Services from a network of gauges across Portland. These gauges operate by collecting rainfall into a cup that tips and empties when 1/100^th of an inch of water is collected. Counting the number of tips in a given time period calculates the accumulated rainfall. Tip count data are frequently transmitted to our databases, allowing rainfall data to be updated for the public on an hourly basis. 

View full size image of Two technicians service a rain meter on top of commercial structure in Downtown Portland, with several tall commercial and residential buildings in the background.

Measuring and providing precipitation data in near real-time provides critical information for Environmental Services employees, including:

• Monitoring stormwater flows and managing sewer system capacity
• Guiding the maintenance and operations of our systems
• Informing long-term infrastructure investment and planning

Historically, Environmental Services only collected and sent rainfall data to the USGS. Our collaboration with USGS utilized their federal platform to host a public website on the USGS.gov domain. In 2025, Environmental Services took over the hosting with the implementation of a new Environmental Data Portal. As we transition and move forward, we welcome feedback from the data user community using the Portland Rainfall Data Portal feedback form.

Important Disclaimers

• No liability: Rainfall data is released on the condition that the City of Portland may not be held liable for any damages resulting from its use.
• Data is provisional: Rainfall data is subject to review and may be adjusted.
• Operational use only: This data is primarily intended for internal planning and analysis. While it may be helpful to the public, Environmental Services does not guarantee its accuracy or fitness for legal or engineering use.
• Data gaps may occur: Periodic gaps in data collection may happen due to maintenance, equipment failure, or connectivity issues.