ROOTED IN REAL DATA Historical data. Thoughtful planning. No weather guarantees.
Montana · NOAA station reference

Bredette
frost dates.

A source-backed view of historical freeze risk at this weather station. Use it to understand the season, not as a promise about your garden or this year’s weather.

Seasonal freeze reference
Modeled annual freeze occurrence: 100%. Date percentiles below are conditional on a cold season containing a 32°F freeze, not all years.
Last spring 32°F freeze · conditional medianMay 20
First fall 32°F freeze · conditional medianSep 21
Days between conditional medians124 days
Uncertainty, made visible

One date never tells
the whole season.

1991–2020 station normals
32°F minimum-temperature threshold

Last spring freeze

Among cold seasons with a freeze: probability of the last occurrence on this date or later.

10%Jun 1
30%May 25
50%May 20Median reference
70%May 15
90%May 8

The 10% date is later in spring than the median: a more cautious historical reference, still not a guarantee.

First fall freeze

Among cold seasons with a freeze: probability of the first occurrence on this date or earlier.

10%Sep 6
30%Sep 16
50%Sep 21Median reference
70%Sep 25
90%Oct 1

The 10% date is earlier in fall than the median: a more cautious harvest-planning reference.

These percentages are conditional on a cold season containing a 32°F freeze; they are not probabilities across all years. They describe historical climate, not this season’s forecast. The spring and fall probability directions are intentionally different. A garden can be warmer or colder than the reference station.

An explicit planning choice

Try a harvest scenario.

If a historical freeze reference fits your crop and regional guidance, you can choose it as a calculator target. This action does not turn the date into a recommended harvest deadline.

Choose a planning year.

Percentiles are conditional on a cold season with a freeze. Some crops tolerate freezing; others need warmth well before it. Check crop and local guidance first.

Know the evidence

The reference
behind the numbers.

Official station name
BREDETTE, MT US
NOAA station ID
USC00241088
Coordinates
48.5156, -105.2992
Station elevation
705 m / 2313 ft
Normal period
1991–2020
Source retrieved
2026-10-02
Source modified
Tue, 27 Jun 2023 15:16:19 GMT
Original NOAA station record
Put the data in context

A baseline.
Not a forecast.

Weather stations measure a particular location. Differences in elevation, exposure, nearby water, terrain and urban heat can change conditions in an individual garden.

  • 32°F is the station air-temperature threshold; visible frost on leaves can differ.
  • Median dates still leave substantial historical freeze risk.
  • Historical normals summarize 1991–2020, not current weather.
  • Crop suitability requires regional horticultural guidance, soil warmth, cultivar and day length.
Understand the method Check the current NWS forecast
Traceable, down to the field

How strong is this reference?

Source variableHistorical dateYearsNOAA completeness
Last spring freeze · 10%Jun 130S · Standard
Last spring freeze · 30%May 2530S · Standard
Last spring freeze · 50%May 2030S · Standard
First fall freeze · 10%Sep 630S · Standard
First fall freeze · 30%Sep 1630S · Standard
First fall freeze · 50%Sep 2130S · Standard

Our ordinary calendar model requires supported dates and standard/representative source quality with at least 10 years. This does not erase local uncertainty.

A wider view

Other Montana references

Explore the state