Frost dates for Pontiac Wastewater Treatment Plant, Michigan
Half of years have their last spring frost by April 26, but 1 year in 10 still frosts after May 12.
A frost date is really a percentile from 30 years of records at a nearby weather station: in about half of years a frost still comes after the median date. Both numbers are below, so you can choose the risk yourself.
The odds
Last spring frost
How often a frost still comes on or after each date.
- 1 year in 10
- May 12
- 1 year in 5
- May 5
- 3 years in 10
- May 2
- 2 years in 5
- April 29
- Half of years (the median)
- April 26
First fall freeze
How often the first freeze comes on or before each date.
- 1 year in 10
- October 7
- 1 year in 5
- October 12
- 3 years in 10
- October 16
- 2 years in 5
- October 20
- Half of years (the median)
- October 22
- Growing season
- about 177 days
- Hardiness zones nearby
- 6a, 6b
- Summer days
- a usual high of about 27 °C80 °F
- Lettuce and spinach run to seed
- June to August, in hot, long days (how we know)
Summer and rain
A growing garden needs about 25 mm1 in of water a week, rain and watering together. Here is what a normal month brings.
Month by month
- January
- high ~0 °C31 °F · low ~-8 °C17 °F · rain ~55 mm2.2 in
- February
- high ~1 °C34 °F · low ~-8 °C18 °F · rain ~48 mm1.9 in
- March
- high ~7 °C44 °F · low ~-3 °C26 °F · rain ~56 mm2.2 in
- April
- high ~14 °C58 °F · low ~2 °C36 °F · rain ~75 mm2.9 in
- May
- high ~21 °C69 °F · low ~9 °C49 °F · rain ~97 mm3.8 in
- June
- high ~26 °C78 °F · low ~15 °C59 °F · rain ~84 mm3.3 in
- July
- high ~28 °C82 °F · low ~17 °C63 °F · rain ~80 mm3.1 in
- August
- high ~27 °C81 °F · low ~16 °C62 °F · rain ~82 mm3.2 in
- September
- high ~23 °C74 °F · low ~12 °C54 °F · rain ~74 mm2.9 in
- October
- high ~16 °C60 °F · low ~6 °C42 °F · rain ~74 mm2.9 in
- November
- high ~9 °C47 °F · low ~0 °C32 °F · rain ~80 mm3.1 in
- December
- high ~2 °C36 °F · low ~-4 °C24 °F · rain ~57 mm2.2 in
Where these numbers come from
NOAA NCEI 1991–2020 Climate Normals, the Pontiac Wastewater Treatment Plant station (listed by NOAA as Pontiac Wwtp, USC00206658), at 42.64, -83.26. These are that station’s own records, unshifted. The further your garden is from it, the less exactly they describe your ground. The planner finds the nearest station to your garden and lowers its confidence with distance, so no number is presented as if it were measured in your garden.
Cold air also pools in low ground on the clear, still nights when frost happens, so a hollow can freeze while a slope a few hundred feet away does not. No table can know that about your garden. A few seasons of your own logged frosts can.
ZIP codes nearest this station
48009, 48017, 48025, 48034, 48072, 48073, 48076, 48083, 48084, 48085, 48094, 48095…
+22 moreShow fewer
48098, 48301, 48302, 48304, 48306, 48307, 48309, 48314, 48316, 48317, 48320, 48326, 48334, 48340, 48341, 48342, 48359, 48360, 48362, 48363, 48367, 48370.
Nearby stations
The nearest stations and how their last-frost dates compare. Together they show how frost varies across your area.
- Detroit City Airport, MI, last frost by April 21
- Dearborn, MI, last frost by May 1
- Grosse Pointe Farms, MI, last frost by April 29
- Linden Wastewater Treatment Plant, MI, last frost by May 3
- Jackson Reynolds Field, MI, last frost by May 1
- Toledo Metcalf Field, OH, last frost by April 20
Other stations in Michigan.
- Greenville 2 NNE, MI, last frost by May 18
- Kent City 2 SW, MI, last frost by May 14
When do I plant? · Where the dates come from
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