Hydrology in Hawaii

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Mouseover the time to see the rainfall: 11 am 2 pm 5 pm 8 pm 11 pm 2 am 5 am 8 am Rainfall Map

This map is meant to be an approximate depiction of the areas that have had rain over the 3 hour period ending at 2, 5, 8 and 11, am and pm. The map is created using a network of rain gauges, so no data is available over the water. This data is not quality controlled, and the map may not be accurate, particularly in areas where there are few gauges.

Routine Products

Drought Information Statements updated monthly as conditions warrant
Hawai`i Rainfall Summary - issued hourly
- Automated Hydrologic Observation Sta Report (AHOS) Issued: 07/26/2025 10:45:00 AM UTC
- 90 day archive updated several times daily
- Graphical Rainfall Summary (includes station locations)
1 Hourly Rainfall Summary - issued hourly
- Hydro-Met Data Report Part 5 Issued: 07/26/2025 09:30:00 AM UTC
- 72 Hour Archive
Daily Hawai`i Cooperative Observations

Additional Hydrology Resources

Cooperative observation location maps:
- Kaua`i
- O`ahu
- Moloka`i/Lana`i
- Maui
- Hawai`i
Ua Net automated rain gage network
Hydronet archived data (online)
Monthly Precipitation Summaries - Click to see the last year's worth of summaries
Click to receive notifications of new summaries
Standardized Precipitation Index (SPI) data for Hawai`i
Click to receive notifications of new SPI information
Daily Streamflow Conditions from the USGS