Signal Hill, California Weather
Summer heat deepens across the valleys. Day 15 of summer. Read this microseason across nine climate regions →
Signal Hill weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 5Foggy——83°63°—
- MondayJul 6Overcast——83°61°0°
- TuesdayJul 7Clear——83°62°0°
- WednesdayJul 8Clear——85°67°+2°
- ThursdayJul 9Clear——77°68°-8°
- FridayJul 10Overcast——76°68°-1°
- SaturdayJul 11Overcast——75°69°-1°
AQI 61 (Moderate), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 18.4 µg/m³, PM10 at 22.5 µg/m³ — typical background levels with no transport signature.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
Ozone × UV × Sky
Ozone at AQI 32 now. With UV 12 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 50 around 1 PM.
- Present
- AQI 32
- UV peak
- 11.7 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 50
PM × Wind × Precip
PM2.5 at 18.4 µg/m³, PM10 at 22.5 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.82
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- background
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
If the first of July be rainy weather, 'twill rain more or less for four weeks together.
- Moonrise
- 11:08 PM
- Moonset
- 11:11 AM
- In sign
- ♓︎ Pisces
Summer heat deepens across the valleys
Signal Hill at a glance
- Today vs. normal: 3°F below the seasonal normal for this latitude
- Last frost: March 10 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
ZIP code: 90755
16-Day Forecast — Signal Hill
- Sun83°63°0%
- Mon83°61°0%
- Tue83°62°0%
- Wed85°67°0%
- Thu77°68°0%
- Fri76°68°0%
- Sat75°69°0%
- Sun85°69°2%
- Mon88°69°6%
- Tue83°71°8%
- Wed88°72°3%
- Thu92°75°10%
- Fri90°73°10%
- Sat86°72°10%
- Sun86°71°19%
- Mon89°71°19%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of July 5, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.
Microseason · July 1–5
Summer heat deepens across the valleys
Inland temperatures exceed 95°F regularly; fire danger reaches moderate to high across most of the region.
Day 186 of 365 · Wedge 37 of 72
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | — | — |
| March | lettuce, peas, spinach, radishes | — |
| April | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | — |
| May | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | — | tomatoes, beans, summer squash |
| August | — | tomatoes, beans, summer squash |
| September | — | tomatoes, beans, summer squash |
| October | fall brassicas, garlic (overwinter), carrots | winter squash, tomatoes (last) |
| November | fall brassicas, garlic (overwinter), carrots | — |
| December | — | — |
A year in weather
Signal Hill's warmest month is August (~73°F mean) and its coldest is January (~54°F). Rainfall peaks in February (2.3 inches) and bottoms out in August (0.0 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 54° | 2.2″ | 9 |
| February | 55° | 2.3″ | 8 |
| March | 57° | 1.8″ | 9 |
| April | 61° | 0.8″ | 7 |
| May | 64° | 0.2″ | 4 |
| June | 67° | 0.0″ | 2 |
| July | 72° | 0.1″ | 1 |
| August | 73° | 0.0″ | 0 |
| September | 71° | 0.0″ | 1 |
| October | 67° | 0.3″ | 3 |
| November | 60° | 1.0″ | 6 |
| December | 54° | 1.7″ | 7 |
Regional context
Drawing on NOAA NCEI 1991-2020 normals, Signal Hill's January averages 54°F and July 72°F — 18°F apart — while precipitation totals roughly 10.6 inches over some 57 days.
Signal Hill's moisture rides winter storm tracks: February brings 2.3 inches over 7.6 wet days, while August sees only 0.0 inches across 0.2 days in the dry warm season. That groups Signal Hill with places like Long Beach, CA, Lakewood, CA and Rossmoor, CA on the same cool-season storm track.
Freezes are uncommon in Signal Hill, where the coldest month averages 54°F; cool-season crops grow fall through spring. Summer heat in August (about 73°F) is the binding constraint, not cold. Signal Hill's coastal lots stay 4-7°F milder overnight than Signal Hill's inland parcels.
Similar climates: Long Beach, CA, Lakewood, CA, Rossmoor, CA, Carson, CA, Hawaiian Gardens, CA.
Frequently asked
- When does it freeze in Signal Hill?
- Frost typically leaves Signal Hill by mid-March and returns to Signal Hill near mid-December.
- What is the rainy season in Signal Hill?
- Signal Hill sees its heaviest rain in February (around 2.3 inches), part of roughly 11 inches a year.
- What is the warmest month in Signal Hill?
- Signal Hill peaks in August, when the mean runs near 73°F.
- What is the coldest month in Signal Hill?
- January is Signal Hill's coldest month, averaging about 54°F.
- When can I start a vegetable garden in Signal Hill?
- Around mid-March, start frost-hardy crops in Signal Hill; tomatoes and basil belong a fortnight later.
- How many rainy days does Signal Hill get?
- Expect roughly 57 wet days a year in Signal Hill.
- What hardiness zone is Signal Hill?
- With January around 54°F, Signal Hill's zone reflects that minimum — the USDA ZIP map confirms Signal Hill's band.
- What is the 10-day forecast for Signal Hill?
- Signal Hill's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
- Will it rain this week in Signal Hill?
- See this week's day-by-day rain chances for Signal Hill in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Signal Hill?
- Current conditions for Signal Hill and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Signal Hill forecast updated?
- The Signal Hill forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Signal Hill?
- Today's sunrise and sunset times for Signal Hill are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter solstice.
- How accurate is the weather forecast for Signal Hill?
- The next few days in Signal Hill's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Climate
In Signal Hill, California, the hot-summer Mediterranean climate runs from about 54°F in January to 72°F in July, a 18°F seasonal range.
In a typical year Signal Hill records about 11 inches of precipitation on around 57 days.
Signal Hill sits at 33.8°N; that 18°F seasonal swing frames planting windows and frost dates across Signal Hill.
ZIP codes in Signal Hill
- 90755