Frost dates for New Haven Tweed Airport, Connecticut
Half of years have their last spring frost by April 17, but 1 year in 10 still frosts after May 1.
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 1
- 1 year in 5
- April 26
- 3 years in 10
- April 22
- 2 years in 5
- April 20
- Half of years (the median)
- April 17
First fall freeze
How often the first freeze comes on or before each date.
- 1 year in 10
- October 11
- 1 year in 5
- October 16
- 3 years in 10
- October 20
- 2 years in 5
- October 24
- Half of years (the median)
- October 27
- Growing season
- about 193 days
- Hardiness zones nearby
- 6b, 7a
- 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 ~3 °C38 °F · low ~-5 °C23 °F · rain ~69 mm2.7 in
- February
- high ~5 °C40 °F · low ~-4 °C24 °F · rain ~72 mm2.8 in
- March
- high ~8 °C47 °F · low ~-1 °C30 °F · rain ~93 mm3.7 in
- April
- high ~14 °C58 °F · low ~4 °C39 °F · rain ~106 mm4.2 in
- May
- high ~20 °C68 °F · low ~10 °C49 °F · rain ~90 mm3.5 in
- June
- high ~25 °C76 °F · low ~15 °C59 °F · rain ~88 mm3.5 in
- July
- high ~28 °C82 °F · low ~19 °C66 °F · rain ~85 mm3.4 in
- August
- high ~27 °C81 °F · low ~18 °C65 °F · rain ~90 mm3.6 in
- September
- high ~24 °C75 °F · low ~14 °C57 °F · rain ~102 mm4 in
- October
- high ~18 °C64 °F · low ~8 °C46 °F · rain ~96 mm3.8 in
- November
- high ~12 °C53 °F · low ~2 °C36 °F · rain ~79 mm3.1 in
- December
- high ~6 °C44 °F · low ~-2 °C29 °F · rain ~90 mm3.5 in
Where these numbers come from
NOAA NCEI 1991–2020 Climate Normals, the New Haven Tweed Airport station (listed by NOAA as New Haven Tweed Ap, USW00014758), at 41.26, -72.89. 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
06405, 06437, 06443, 06471, 06473, 06510, 06511, 06512, 06513, 06515, 06516, 06517, 06519.
Nearby stations
The nearest stations and how their last-frost dates compare. Together they show how frost varies across your area.
- Bridgeport Sikorsky Mem Airport, CT, last frost by April 5
- Meriden Markham Municipal Airport, CT, last frost by April 26
- Shirley Brookhaven Airport, NY, last frost by April 18
- Islip Li Macarthur Airport, NY, last frost by April 10
- Hartford Brainard Field, CT, last frost by April 17
- Bakersville, CT, last frost by May 8
Other stations in Connecticut.
- Storrs, CT, last frost by April 19
When do I plant? · Where the dates come from
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