A computer's guess at future radar. The rock does not endorse the future.
2h agonow+30m
The Rocktionary: every weather term, explained by a rock
Rockreation: pick a game
Hanging out: Tic Tac Toe
The Rockord Book
All records live on this device. The rock keeps no receipts. You keep them.
Rock, Time, Weather
?vs?
Time grinds rock. Rock endures weather. Weather does not care what year it is.
The weather you throw is whatever is outside right now.
Rocktoid or Rubbish
Rocktoid, or rubbish?
Warmer or Colder
Asking both towns...
or
Name That Sky
What is the rock standing in?
Weather Rocktoid
A new Rocktoid every midnight. The rock reads a lot.
The rock's instrument panel
Reading the instruments...
Remote Rocks: station a rock anywhere you love
Put a rock in Mom's yard, the lake house, a kid's college town. Each one stands in that sky and reports it here. Tap a rock for its forecast; the pencil renames it.
Tap me on the shoulder turns on browser notifications: when a warning or watch lands on one of your rocks, you get a notification, as long as the site is open in a tab somewhere.
Remote Rocks live on this device. We do not track you, so a rock you station on your phone will not appear on your computer or tablet, and the other way around. That is the privacy working, not a bug. Forecasts and alerts travel from here straight to the weather services, same as always.
Settings
ToneHow the site dresses. System follows your device.
Shoulder tapsBrowser notifications when a warning lands on one of your Remote Rocks. Only while the site is open in a tab.
Keep me in your pocketPut the rock on your home screen. Same site, no store, no middleman, and it opens even with no signal.
This deviceEverything the rock remembers lives right here: your town, your rocks, your settings, your tic tac toe record. One tap and it is all forgotten.
Build
Keep me in your pocket
Same site, no store, no middleman. I get my own icon, I open full screen, and I still open when you have no signal.
Tap your browser's own Share or menu button: the square with the arrow on an iPhone, the ⋮ or ⋯ menu in the corner on most others. It has to be the browser's button; websites are not allowed to press it for you.
Find and tap Add to Home Screen. Some browsers call it Install.
Confirm. That is the whole ceremony.
Cahokia Heights, IL Weather
Cahokia Heights, Illinois sits at 38.5721, -90.1553. Its warmest month is July, when the day usually reaches 89F, and its coldest is January, when the night usually falls to 24F. May is the wettest, with rain on about 14 days. The hottest day in the station record is 107F on June 28, 2012, and the coldest night -14F on January 7, 2014. This page carries live conditions, an hour by hour timeline, a ten day outlook, radar, monthly averages and searchable daily history back to 1940.
About Cahokia Heights weather
Cahokia Heights sits at 38.5721, -90.1553 and covers about 15.784 square miles. The forecast above is live: current conditions lead with the HRRR model, corrected against the nearest reporting station and against radar overhead, because a model can lag a storm and the radar cannot.
The tabs at the top of this page carry the hour by hour timeline, the ten day outlook and live radar. Where the models disagree about a day, the rock says so on the day rather than quietly picking a winner.
The rock grades itself against what actually happened and publishes the result whether it flatters it or not. Those standings live in the Receipts.
Where these numbers come from
Current conditions and forecast: NOAA forecast grids (the National Weather Service digital forecast, the National Blend of Models, HRRR and GFS) decoded on our own server, corrected against the nearest reporting station and our own radar. Open-Meteo is consulted only as a fallback when our server is silent.
Radar: NOAA MRMS merged reflectivity, rendered into tiles by myweatherrock.
Monthly averages and records: computed by myweatherrock from NOAA GHCN-Daily station records at the nearest qualifying station, named on this page with its distance. Measurements, not estimates.
Daily history search: the town's own NOAA GHCN-Daily station file, held on our server, measurements by day. Months the station missed fall back to the Open-Meteo historical archive (reanalysis), and the page says so when it does.
What the weather is usually like in Cahokia Heights
Cahokia Heights is warmest in July, when the day usually reaches 89F, and coldest in January, when the night usually falls to 24F. May is the wettest month, with rain on about 14 days of it.
Usual high and low, by month
Days with rain, by month
The same year as numbers
Month
Usual high
Usual low
Rain days
Snow days
January
41F
24F
7
0
February
46F
27F
8
0
March
57F
36F
10
0
April
68F
46F
11
0
May
77F
56F
14
0
June
86F
64F
10
0
July
89F
68F
9
0
August
88F
66F
10
0
September
82F
57F
9
0
October
70F
46F
8
0
November
56F
35F
8
0
December
44F
27F
8
0
Thirty-year normals, 1991 to 2020, computed from the daily record, measured at the Cahokia St Louis Dwtn Ap station 0.7 miles away. A rain day means at least a hundredth of an inch fell, the same measurable-precipitation mark the Weather Service uses. Source: computed from the station record, NOAA GHCN daily.
Cahokia Heights weather history, back to 1940
Pick any month back to 1940 and see what the archive holds for Cahokia Heights: the reanalysis record of what happened, day by day.
Reading this month last year to start you off.
Cahokia Heights weather records
In 34,177 days of observations Cahokia Heights has been as hot as 107F and as cold as -14F. Not averages: the actual days.
Hottest day
107F
June 28, 2012
Coldest night
-14F
January 7, 2014
Wettest day
7.23 in
July 26, 2022
Biggest snow
12.0 in
December 19, 1973
NOAA GHCN daily station records, observed 1997 to 2025: temperature at the Cahokia St Louis Dwtn Ap station, 0.7 miles away; snowfall at the St Louis Sci Ctr station, 7.4 miles away. Station measurements, not estimates. Record dates reflect the station's own observation schedule, and the official state record may live at a different station.
Common questions about Cahokia Heights weather
Common questions
What is the weather usually like in Cahokia Heights, IL?
Cahokia Heights is warmest in July, when the day usually reaches 89F, and coldest in January, when the night usually falls to 24F. Rain falls on roughly 112 days a year, most often in May. Averages are thirty-year normals, 1991 to 2020, computed from the nearest NOAA station's own daily record.
How much does it rain in Cahokia Heights, IL?
About 112 days a year see at least a hundredth of an inch, which is the Weather Service's measurable-precipitation mark. May is the wettest month with rain on about 14 of its days, and January the driest with about 7.
What is the hottest it has ever been in Cahokia Heights, IL?
The hottest day measured for Cahokia Heights reached 107F on June 28, 2012, and the coldest night -14F on January 7, 2014. Both are real NOAA station measurements from the GHCN daily archive, observed 1997 to 2025, at the Cahokia St Louis Dwtn Ap station. Not estimates, though the official state record may live at a different station.
Can I look up past weather for Cahokia Heights, IL?
Yes, and for free. The History tab on this page takes any month back to 1940 and shows every day of it: the high, the low, what fell, and that month's hottest and coldest day. No account and no payment.
Is the Cahokia Heights forecast on this page free, and does it track me?
It is free, carries no advertising, and needs no account. Nothing about a visitor leaves the device except the coordinates needed to fetch a forecast, and those are not stored against anyone.