Hottest (avg)
#8 / 12
Sits around the middle of the year.
September in context
How it compares to the rest of the year in Mexico City.
Wettest (avg)
#1 / 12
The wettest month of the year.
Daylight Hours
#6 / 12
Around the yearly average.
Windiest (avg)
#9 / 12
Close to the yearly wind average.
Highest UV
#7 / 12
Near the middle of the yearly UV range.
Most Humid
#1 / 12
The muggiest month of the year.
Monthly climate breakdown
A detailed look at the typical climate conditions for September.
Thermal profile
Temperature
Typical daytime high
- Nighttime low
-
- Feels like (avg)
-
Light window
Sunshine
12.2 h
Average daylight
- UV index (max)
- 10
- Typical sun hours
- 06:23 - 18:38
Wet-day pattern
Rain & Snow
Typical rainfall
- Rainy days
- 24 days
- Cloud cover (avg)
- 80%
Air feel
Humidity & Wind
79%
Average humidity
- Wind (avg)
-
- Wind (max gusts)
-
Historical daily baseline
Daily climate explorer
Pick a day to inspect the usual conditions through September in Mexico City. Based on a 30-year historical climate baseline, not a forecast.
Primary control
Select a day
Scroll to compare daily conditions. The summary updates with your selection.
Secondary context
Monthly trend
Median daytime highs across the month, with a softer low line.
Median temperatureMedian lowTypical range
Day 15 selected for September. Temperature 21.2°C.
Historical disruption baseline
Typical disruptions in September
Based on 30 years of historical data, these are the disruption patterns most likely to affect plans in September.
Rain High impact
Rain disruption Measures: Likely rain disruption days. Observed about 42% of days (12.5 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
12.5 days / month
- Share of days
- ~42% of days
- Upper edge
- Up to ~26mm (P95)
Why this matters
Rain disruption risk appears on ~13 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Washout risk Measures: Washout day risk. Observed about 41% of days (12.3 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
12.3 days / month
- Share of days
- ~41% of days
- Upper edge
- Up to ~26mm (P95)
Why this matters
Washout conditions are possible on ~12 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Heavy rain days Measures: Heavy rain days (>=10mm). Observed about 23% of days (6.8 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
6.8 days / month
- Share of days
- ~23% of days
- Upper edge
- Up to ~28mm (P95)
Why this matters
Heavy rain is possible on ~7 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Visibility Minor
Fog-likely signal Measures: Fog-likely visibility proxy. Observed about 3% of days (0.9 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.9 days / month
- Share of days
- ~3% of days
- Upper edge
- Up to ~95% (P95)
Why this matters
Fog-likely conditions are possible on ~1 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Show all disruptions (11 more)
Rain High impact
Washout run Measures: Multi-day washout runs. Observed about 2.9 days/month in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
2.9 days / month
- Share of days
- —
- Upper edge
- Up to ~26mm (P95)
Why this matters
Multi-day washout runs are possible on ~3 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Very heavy rain Measures: Very heavy rain days (>=25mm). Observed about 2% of days (0.7 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.7 days / month
- Share of days
- ~2% of days
- Upper edge
- Up to ~40mm (P95)
Why this matters
Very heavy rain is possible on ~1 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain Minor
Wet days Measures: Wet days (>=0.1mm). Observed about 86% of days (25.8 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
25.8 days / month
- Share of days
- ~86% of days
- Upper edge
- Up to ~22mm (P95)
Why this matters
Measurable rain is possible on ~26 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Cloud Minor
Cloudy days Measures: Cloudy days (cloud cover >=60%). Observed about 85% of days (25.6 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
25.6 days / month
- Share of days
- ~85% of days
- Upper edge
- Up to ~100% (P95)
Why this matters
Cloudy skies are possible on ~26 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Rain Minor
Rainy hours Measures: Rain-hours signal (>=3h rain). Observed about 79% of days (23.6 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
23.6 days / month
- Share of days
- ~79% of days
- Upper edge
- Up to ~22h (P95)
Why this matters
Several rainy hours are possible on ~24 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain Minor
Wet most of day Measures: Wet-most-of-day signal (>=6h rain). Observed about 65% of days (19.6 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
19.6 days / month
- Share of days
- ~65% of days
- Upper edge
- Up to ~22h (P95)
Why this matters
Wet-most-of-day conditions are possible on ~20 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Cloud Minor
Mostly cloudy days Measures: Mostly cloudy days (cloud cover >=80%). Observed about 62% of days (18.6 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
18.6 days / month
- Share of days
- ~62% of days
- Upper edge
- Up to ~100% (P95)
Why this matters
Mostly cloudy skies are possible on ~19 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Humidity Minor
High humidity Measures: High humidity days (RH >=80%). Observed about 53% of days (15.8 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
15.8 days / month
- Share of days
- ~53% of days
- Upper edge
- Up to ~90% (P95)
Why this matters
High humidity is possible on ~16 days. Comfort and pace can drop quickly, so plan shorter outdoor blocks with air-conditioned backup stops.
Cloud Minor
Overcast days Measures: Overcast days (cloud cover >=95%). Observed about 24% of days (7.3 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
7.3 days / month
- Share of days
- ~24% of days
- Upper edge
- Up to ~100% (P95)
Why this matters
Overcast skies are possible on ~7 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Wind Minor
Gusty days Measures: Gusty days (>=40 km/h). Observed about 8% of days (2.4 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
2.4 days / month
- Share of days
- ~8% of days
- Upper edge
- Up to ~48km/h (P95)
Why this matters
Gusty conditions are possible on ~2 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Other Minor
Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data Measures: Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data. Observed about 3% of days (0.9 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.9 days / month
- Share of days
- ~3% of days
- Upper edge
- Up to ~95 (P95)
Why this matters
Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data is possible on ~1 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Travel planning FAQ
Frequently asked questions
Quick answers to the weather questions you ask the most.
Is September a good time to visit Mexico City?
Typical September days in Mexico City reach highs of 21°C (70°F) with nights around 12°C (54°F). It usually feels mild by day and cool after dark. It is among the wetter months, so it is wise to have some indoor backup plans or flexible activities.
What are temperatures like in September?
Daytime temperatures in September typically peak near 21°C (70°F), while nights drop to around 12°C (54°F). Expect mild afternoons and cool evenings.
How much does it rain in September?
Rainfall in September averages 185 mm (7.3 in) across roughly 24 days. Overall it is a very wet time of year, so a light rain jacket and waterproof shoes are very handy.
How many hours of daylight are there in September?
You can expect about 12 hours of daylight in September. Sunrise is typically around 06:23 and sunset near 18:38. Daylight is fairly typical, with enough time for sightseeing.
How strong is the sun in September?
UV levels frequently reach very high levels (around 10), so strong sun protection is essential, especially around midday.
Is it windy in September?
In September, average wind speeds are around 6 km/h (4 mph), with gusts on the windiest days reaching about 39 km/h (24 mph). On the ground, it is a gentle to moderate breeze is common, but stronger winds are not frequent.