Historical Rainfall Checker
Enter your jobsite location to review precipitation from the last 30 days, then compare it with your permit-defined inspection schedule.
Use the threshold in your permit
Inspection schedules and rain thresholds vary by permit and permitting authority. Under the 2022 EPA CGP, one available schedule combines inspections every 14 calendar days with inspections after a storm producing 0.25 inches or more of rain within 24 hours.
- Confirm the schedule elected for your project.
- Confirm how the permit defines a qualifying storm and its inspection deadline.
- Use the selector above only after checking those project-specific requirements.
Some state permits use different thresholds or schedules. Historical gridded weather data is a useful cross-check, but it may not replace an on-site gauge or another measurement method required by your permit.
Keep a traceable weather record
Record the gauge or weather-station source required by your permit, the observation period, and the measured amount. If equipment is damaged or data is missing, document the issue rather than reconstructing a record without support.
Open-Meteo data vs. on-site gauges
This tool uses the Open-Meteo historical archive. Treat it as a screening and cross-checking aid. Follow the measurement source and recordkeeping method specified by the applicable permit.
What if I missed an inspection?
If you discover a past rain event that you missed:
- Do NOT backdate your report. This is fraud.
- Conduct an inspection immediately.
- Note the gap in your SWPPP Corrective Action Log.
- Document the process change you will use to prevent recurrence.