Thornton, CO hail history
Every radar-indicated hail event over Thornton, CO since 2020, year by year, from MRMS (NOAA/NWS).
Demo data
- 14days with an event on record
- 6seasons covered
- moderatehighest class on record
- 08/22/2026most recent event
The most recent radar-indicated hail over Thornton was on August 22, 2026, at class light, corroborated by a human report 2.8 km away.
Population: 141,867 · ZIP codes covered: 8 (80229, 80233, 80241, 80260…) · Adams County
Public hail map — Thornton, CO
Public traffic cameras — live view; verified = validated image, not damage.
Radar-indicated — not ground-confirmed
SPC Day 1-3 — FORECAST (estimate). Not a NIMBUS alert.
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SPC forecast — severe-convection probability
- 5%
- 10%
- 15%
- 30%
- 45%
- 60%
- CIG — conditional severe hail
SPC Day 1-3 — FORECAST (estimate). Not a NIMBUS alert.
Source: Storm Prediction Center (NOAA/NWS) official convective outlooks. Not NIMBUS data.
Tap the map or type a ZIP code to read that location.
Location reading
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Estimated intensity
- no signal — Below the event threshold. Radar indicated no relevant hail.
- light — Above the event threshold, in the lowest band of the archive.
- moderate — Mid band of the historical archive.
- severe — High band — most body-damage events land here.
- extreme — Top of the historical archive. Rare.
Ordinal class from measured percentiles. Colors show relative radar signal strength — not hail size.
Technical detail of the 11 bands
MESH quantization bands in inches. This is the internal radar reading, not a hail size measurement (measured correlation r=0.31).
| # | MESH | Class |
|---|---|---|
| 1 | 0.25–0.49 in | no signal |
| 2 | 0.50–0.74 in | light |
| 3 | 0.75–0.99 in | light |
| 4 | 1.00–1.17 in | light |
| 5 | 1.18–1.49 in | moderate |
| 6 | 1.50–1.69 in | moderate |
| 7 | 1.70–1.99 in | severe |
| 8 | 2.00–2.13 in | severe |
| 9 | 2.14–2.99 in | extreme |
| 10 | 3.00–3.99 in | extreme |
| 11 | ≥ 4.00 in | extreme |
light: 0.50–1.17 in · moderate: 1.18–1.69 in · severe: 1.70–2.13 in · extreme: ≥ 2.14 in
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Most recent events
| Date | Class | Evidence | Nearest report | ZIP codes covered |
|---|---|---|---|---|
| 08/22/2026 | light | A | 2.8 km | 80233, 80241, 80602 |
| 08/14/2026 | light | B | 25.5 km | 80233, 80602 |
| 06/08/2026 | light | B | 7.4 km | 80229 |
| 06/01/2026 | light | B | 6.7 km | 80229 |
| 06/17/2025 | light | A | 0 km | 80229, 80233, 80241, 80260, 80602 |
| 06/01/2025 | light | B | 164.6 km | 80229, 80241, 80602 |
Year by year
| Year | Days with an event | Peak class | Strongest day |
|---|---|---|---|
| 2020 | 0 | no signal | No event on record. |
| 2021 | 2 | light | 09/03/2021 |
| 2022 | 1 | light | 08/06/2022 |
| 2023 | 4 | light | 06/06/2023 |
| 2024 | 1 | moderate | 05/31/2024 |
| 2025 | 2 | light | 06/17/2025 |
| 2026 | 4 | light | 06/01/2026 |
Strongest events on record
| Date | Class | Evidence | Nearest report | ZIP codes covered |
|---|---|---|---|---|
| 05/31/2024 | moderate | B | 115.6 km | 80229, 80233, 80241, 80260, 80602 |
| 06/06/2023 | light | B | 21.1 km | 80602 |
| 09/03/2021 | light | B | 31.2 km | 80602 |
| 06/22/2023 | light | B | 15.3 km | 80229, 80233, 80241, 80602 |
| 06/17/2025 | light | A | 0 km | 80229, 80233, 80241, 80260, 80602 |
A — corroborated: Radar above threshold plus a human report (LSR/SPC) within 5 km, same day. · B — radar-indicated: Radar above threshold, no nearby human report that day. · C — weak signal: Radar below the event threshold. Does not support a damage claim.
The honest Colorado caveat
The Denver metro is where this method performs worst in the entire country: radar misses roughly 1 in 4 ground-confirmed events. No shading here is not proof that no hail fell.
Frequently asked questions
Did it hail in Thornton in 2026?
Yes. The NIMBUS archive records 4 day(s) of radar-indicated hail over Thornton in 2026. The strongest day was June 01, 2026, at class light.
How does NIMBUS know hail hit Thornton?
We use MRMS (NOAA/NWS), which merges the whole NEXRAD network and estimates hail on a 0.01° grid (about 1 km). A day enters the archive when the signal exceeds 0.5 in of MESH over the ZIP plus a 5 km buffer. It is a radar-indicated event — not a ground confirmation.
Does the map show how big the hail was?
No, and no honest radar map does. We measured the correlation between radar signal and observer-reported size: r=0.311. That is far too weak to publish inches as if they were size. That is why NIMBUS uses classes (light, moderate, severe, extreme) instead of a number.
How often is radar wrong in Thornton?
Often, and we say so on purpose. The Denver metro is where this method performs worst in the country: radar catches about 77.7% of ground-confirmed events, and cell-by-cell precision is 36.4%. In plain terms: shading on the map is strong evidence, but no shading is not proof that no hail fell.
What was the strongest event on record for Thornton?
May 31, 2024, at class moderate and evidence level B, with a human report 115.6 km away. Most affected ZIP codes: 80229, 80233, 80241, 80260, 80602.
How many hail days does Thornton usually get per year?
About 2.3 days per season — that is 14 radar-indicated hail days across 6 season(s) on record. The busiest season was 2023, with 4 day(s). Each "day" is a day when MESH exceeded 0.5 in over some Thornton ZIP code plus the 5 km buffer.
When is hail season in Thornton?
Across the 10 events listed on this page (the strongest and the most recent), the dates fall between May and September. That is the Front Range convective window: hail clusters in spring and summer, and that is when watching your ZIP code pays off.
How do I get alerted when hail hits my ZIP code?
Enter your ZIP code and email in the form on this page. We send a confirmation link by email: alerts start only after you click it. We never ask for a phone number, we never call, and one click unsubscribes.