Deconstruct Sun

St. Petersburg, FL: Hardiness Zone 10b & Sunlight by Season

St. Petersburg is in USDA hardiness zone 10b. Here’s what that means for winter, plus sunrise, sunset, daylight hours and the sun’s path through the year.

Hardiness zone
10b
2023 USDA map
Coldest winter night (avg)
35 to 40 °F
1.7 to 4.4 °C
Longest day (Jun 21)
13h 54m
6:35 AM – 8:29 PM
Shortest day (Dec 21)
10h 23m
7:17 AM – 5:40 PM

Zone 10b in St. Petersburg

On the 2023 USDA Plant Hardiness Zone Map, St. Petersburg falls in zone 10b. That means the coldest night of a typical winter drops to between 35 and 40 °F. Perennials, shrubs and trees labeled for zone 10b or colder (a lower number) should survive the winter here. Parts of the area sit near the boundary with zone 10a, so a sheltered courtyard or an exposed hilltop can behave like the neighboring zone.

A zone only covers winter cold. For a plant to do well it also needs the right amount of sun, and that varies far more from one corner of a yard to the next than the zone does across town.

This is not the official USDA Plant Hardiness Zone Map. Zones are derived from the official 2023 dataset, resampled to about 2 km.

Nearby cities

All Florida hardiness zones →

The sun over St. Petersburg

On the June solstice the sun rises in the northeast at 6:35 AM and climbs to 86° above the horizon at 1:32 PM. On the December solstice the noon sun reaches only 39°, so a 20-foot tree casts a noon shadow about 25 feet long. In June the same tree’s noon shadow is only 2 feet.

0°15°30°45°60°75°90°NNEESESSWWNWN
June solsticeMarch & September equinoxDecember solstice

Open the interactive sun calculator for St. Petersburg

Sunrise, sunset & daylight by month

DateSunriseSunsetDaylightNoon sun
Jan 217:21 AM6:02 PM10h 41m42°
Feb 217:02 AM6:26 PM11h 23m52°
Mar 217:33 AM7:42 PM12h 09m63°
Apr 216:59 AM7:59 PM12h 59m74°
May 216:38 AM8:16 PM13h 38m82°
Jun 216:35 AM8:29 PM13h 54m86°
Jul 216:47 AM8:26 PM13h 38m83°
Aug 217:04 AM8:02 PM12h 59m74°
Sep 217:18 AM7:28 PM12h 09m63°
Oct 217:34 AM6:55 PM11h 21m51°
Nov 216:56 AM5:36 PM10h 40m42°
Dec 217:17 AM5:40 PM10h 23m39°

Local time (New York), including daylight saving time. “Noon sun” is the sun’s height above the horizon at solar noon.

Daylight through the year

0h6h12h18h24hJanuary: 10h 41mJanFebruary: 11h 23mFebMarch: 12h 09mMarApril: 12h 59mAprMay: 13h 38mMayJune: 13h 54mJunJuly: 13h 38mJulAugust: 12h 59mAugSeptember: 12h 09mSepOctober: 11h 21mOctNovember: 10h 40mNovDecember: 10h 23mDec

What “full sun” means in St. Petersburg

Full sun is 6+ hours of direct sun. In St. Petersburg an open spot has 13.9 hours of daylight to work with in June and 10.4 in December, so a bed that clears 6 hours in summer can easily drop to part shade in winter once the low sun slips behind trees and houses.

Full sun6+ hoursof direct sun
Part sun4–6 hoursof direct sun
Part shade2–4 hoursof direct sun
Full shadeUnder 2 hoursof direct sun

Measure the sun in your St. Petersburg yard

Daylight is the ceiling. Deconstruct Sun traces the trees and buildings around one exact spot and tells you its real direct-sun hours, today and at every solstice and equinox.

Download on the App Store

Questions

What hardiness zone is St. Petersburg, FL in?

St. Petersburg, Florida is in USDA plant hardiness zone 10b on the 2023 map. The average coldest winter night is 35 to 40 °F (1.7 to 4.4 °C). It is near the boundary with zone 10a.

How many hours of daylight does St. Petersburg get?

About 13.9 hours on the June solstice (sunrise 6:35 AM, sunset 8:29 PM) and 10.4 hours on the December solstice (sunrise 7:17 AM, sunset 5:40 PM). Around the equinoxes it is close to 12 hours.

How many hours of sun does my St. Petersburg yard get?

Up to the daylight hours above, minus whatever trees, buildings and fences block. In winter, when the sun stays low, that can be most of it. The Deconstruct Sun iPhone app measures the real direct-sun hours for one exact spot by having you trace what is around it.

When is the best time to plant in St. Petersburg?

Zone 10b tells you which perennials survive winter, not planting dates. For timing, use your local average frost dates from your county extension office, and choose plants rated for zone 10b or colder.

Source: USDA Plant Hardiness Zone Map, 2023. Agricultural Research Service, U.S. Department of Agriculture, planthardiness.ars.usda.gov. Underlying data © PRISM Group, Oregon State University, prism.oregonstate.edu, accessed 2026-08-30. Sun times calculated for 27.763, -82.644.