Bourn-Roth Estate · Photo: Sukuru · CC BY-SA 3.0Few U.S. towns have cooler summers than Emerald Lake Hills
On a normal January night the air cools to about 40°. Expect the heaviest rain or snow in December and the lightest in July. Winters are mild: January nights here are milder than in 89% of U.S. towns. The outdoor season runs from March to November, with highs of 64–79°.
A year in Emerald Lake Hills at a glance
Each month’s typical high and low, and what it brings.
What stands out about Emerald Lake Hills’ climate
Compared with towns across the U.S., with Emerald Lake Hills’ place in California beside it.
What a year in Emerald Lake Hills feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
A freeze most winters
Frost and day counts come from NOAA’s station at Redwood City, CA, 1.7 miles from the town’s center, 310 ft lower.
The 2023 USDA map puts Emerald Lake Hills’ center in zone 9b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 30°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 23 inches of rain a year
December is the wettest month and July the driest. Rain falls on about 55 days a year. Snow is rare: about 0.0" in a normal year at Redwood City, CA, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Emerald Lake Hills
84% of the work is heating. Months averaging under 55° run from November through March.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Redwood City, CA.
Living with Emerald Lake Hills’ climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
Zone 9b. Frost comes about 9 winters in 10, so tender plants can often stay out through winter.
Months with highs of 62–84° and lows of 40° or more: March, April, May, June, July, August, September, October and November. 1.3 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Emerald Lake Hills from natural hazards, earthquakes are the largest share (71%); heat waves, cold waves, winter storms and ice storms together are 1%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Emerald Lake Hills and its neighbors
Every town next door is within a degree of Emerald Lake Hills in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Emerald Lake Hills’, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Emerald Lake Hills, CA | 40° | 79° | 23" | 0.0" |
| Poulsbo, WA | 35° | 75° | 33" | 3.0" |
| Makawao, HI | 53° | 75° | 23" | 0.0" |
| Tualatin, OR | 36° | 81° | 40" | 1.0" |
| Hayden, ID | 25° | 83° | 26" | 27" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Emerald Lake Hills averaged 1.7° warmer than the 1900s. The biggest change is in January (+2.2°).
A bigger shift than in 74% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Emerald Lake Hills compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Emerald Lake Hills’ place among California’s.
Emerald Lake Hills weather by month
Highs, lows and precipitation from NOAA’s grid at Emerald Lake Hills’ center; snow, wet days and snow on the ground from Redwood City, CA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 59° | 40° | 4.5" | 0.0" | 9 | 0 | 46° – 54° |
| February | 61° | 42° | 4.5" | 0.0" | 9 | 0 | 48° – 57° |
| March | 64° | 44° | 3.5" | 0.0" | 9 | 0 | 49° – 59° |
| April | 67° | 45° | 1.6" | 0.0" | 5 | 0 | 52° – 59° |
| May | 71° | 49° | 0.7" | 0.0" | 3 | 0 | 56° – 65° |
| June | 76° | 51° | 0.2" | 0.0" | 1 | 0 | 60° – 66° |
| July | 79° | 54° | 0.0" | 0.0" | 0 | 0 | 63° – 70° |
| August | 79° | 54° | 0.0" | 0.0" | 0 | 0 | 65° – 70° |
| September | 79° | 53° | 0.1" | 0.0" | 1 | 0 | 63° – 70° |
| October | 74° | 49° | 1.0" | 0.0" | 3 | 0 | 59° – 67° |
| November | 65° | 44° | 2.3" | 0.0" | 6 | 0 | 49° – 57° |
| December | 59° | 40° | 4.5" | 0.0" | 9 | 0 | 46° – 54° |
| Year | 69° | 47° | 22.8" | 0.0" | 55 | 0 |
How much a month can swing
A normal is an average. March swings the most: from 1991 to 2020 its average ranged from 49° to 59°. August is the most reliable, staying within 5°.
Where Emerald Lake Hills’ numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Emerald Lake Hills’ center.
- Snow: Redwood City, CA (NOAA station in town).
- Frost, freezing nights, 90° and 100° days, heating and cooling: Redwood City, CA, 1.7 miles from the town’s center, 310 ft lower; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Emerald Lake Hills’ climate
What is the weather like in Emerald Lake Hills?
A typical July afternoon reaches 79°, a January night drops to 40°, and snow is almost unheard of. Milder January nights than 89% of U.S. towns; cooler July afternoons than 95% of U.S. towns.
How cold does it get in Emerald Lake Hills in winter?
December nights average 40°. About 6 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 46°.
How much snow does Emerald Lake Hills get?
About 0.0 inches in a normal winter at Redwood City, CA, so most winters see none.
How hot does it get in Emerald Lake Hills?
July, with a typical high of 79° and a low of 54°. About 18 days a year reach 90° and 2 reach 100° (Redwood City, CA).
When is the first and last frost in Emerald Lake Hills?
There is no reliable frost date: a 32° night comes in about 88% of winters at Redwood City, CA, so most years bring a freeze but some pass without one.
What growing zone is Emerald Lake Hills in?
Zone 9b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 30°.
What is the best time of year to visit Emerald Lake Hills?
By one simple rule (highs of 62–84° and lows of 40° or more), March, April, May, June, July, August, September, October and November. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Emerald Lake Hills getting warmer?
Yes: 1991–2020 averaged 1.7° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 74% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Emerald Lake Hills.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.