Avg High
Mexico City in September
Avg Low
Rain
Daylight
12h
What to expect
September in Mexico City is early autumn, a shoulder-season window, so you can get a bit of variety across the month. The month is mostly mild for steady exploring, with a noticeable cool-down after sunset. Most days feel close to what the averages suggest, with straightforward pacing. The daylight window is balanced for full days without endless late evenings.
September in context
How it compares to the rest of the year in Mexico City.
Hottest (avg)
#8 / 12
Wettest (avg)
#1 / 12
Daylight Hours
#6 / 12
Windiest (avg)
#9 / 12
Highest UV
#7 / 12
Most Humid
#1 / 12
Monthly climate breakdown
Temperature
- Daytime high
-
- Nighttime low
-
- Feels like (avg)
-
Sunshine
- Daylight hours
- 12.2 h
- UV index (max)
- 10
- Typical sun hours
- 06:23 - 18:38
Rain & Snow
- Total rain
-
- Rainy days
- 24 days
- Cloud cover (avg)
- 80%
Humidity & Wind
- Humidity (avg)
- 79%
- Wind (avg)
-
- Wind (max gusts)
-
Daily climate explorer
Day 15 selected for September. Typical high 21.2°C and low 12.5°C.
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.
12.5 days / month
~42% of days
Why this matters
- Expected days 12.5 days / month
- Probability ~42% of days
- Intensity Up to ~26mm (P95)
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.
12.3 days / month
~41% of days
Why this matters
- Expected days 12.3 days / month
- Probability ~41% of days
- Intensity Up to ~26mm (P95)
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.
6.8 days / month
~23% of days
Why this matters
- Expected days 6.8 days / month
- Probability ~23% of days
- Intensity Up to ~28mm (P95)
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.
0.9 days / month
~3% of days
Why this matters
- Expected days 0.9 days / month
- Probability ~3% of days
- Intensity Up to ~95% (P95)
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.
2.9 days / month
Probability unavailable
Why this matters
- Expected days 2.9 days / month
- Probability —
- Intensity Up to ~26mm (P95)
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.
0.7 days / month
~2% of days
Why this matters
- Expected days 0.7 days / month
- Probability ~2% of days
- Intensity Up to ~40mm (P95)
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.
25.8 days / month
~86% of days
Why this matters
- Expected days 25.8 days / month
- Probability ~86% of days
- Intensity Up to ~22mm (P95)
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.
25.6 days / month
~85% of days
Why this matters
- Expected days 25.6 days / month
- Probability ~85% of days
- Intensity Up to ~100% (P95)
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.
23.6 days / month
~79% of days
Why this matters
- Expected days 23.6 days / month
- Probability ~79% of days
- Intensity Up to ~22h (P95)
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.
19.6 days / month
~65% of days
Why this matters
- Expected days 19.6 days / month
- Probability ~65% of days
- Intensity Up to ~22h (P95)
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.
18.6 days / month
~62% of days
Why this matters
- Expected days 18.6 days / month
- Probability ~62% of days
- Intensity Up to ~100% (P95)
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.
15.8 days / month
~53% of days
Why this matters
- Expected days 15.8 days / month
- Probability ~53% of days
- Intensity Up to ~90% (P95)
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.
7.3 days / month
~24% of days
Why this matters
- Expected days 7.3 days / month
- Probability ~24% of days
- Intensity Up to ~100% (P95)
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.
2.4 days / month
~8% of days
Why this matters
- Expected days 2.4 days / month
- Probability ~8% of days
- Intensity Up to ~48km/h (P95)
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.
0.9 days / month
~3% of days
Why this matters
- Expected days 0.9 days / month
- Probability ~3% of days
- Intensity Up to ~95 (P95)
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.
Frequently asked questions
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.