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October Weather in Ann Arbor Michigan, United States

Daily high temperatures decrease by 12°F, from 67°F to 55°F, rarely falling below 42°F or exceeding 79°F.

Daily low temperatures decrease by 9°F, from 48°F to 38°F, rarely falling below 28°F or exceeding 59°F.

For reference, on July 19, the hottest day of the year, temperatures in Ann Arbor typically range from 63°F to 84°F, while on January 29, the coldest day of the year, they range from 17°F to 31°F.

Average High and Low Temperature in October in Ann Arbor

The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on October. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Average Hourly Temperature in October in Ann Arbor

Average Hourly Temperature in October in Ann ArborOct112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMSepNovvery coldcoldcoolcomfortablewarm
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.

Novopavlovsk, Russia (5,654 miles away) is the far-away foreign place with temperatures most similar to Ann Arbor (view comparison).

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The month of October in Ann Arbor experiences increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 37% to 48%.

The clearest day of the month is October 1, with clear, mostly clear, or partly cloudy conditions 63% of the time.

For reference, on January 10, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 64%, while on August 23, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 67%.

Cloud Cover Categories in October in Ann Arbor

Cloud Cover Categories in October in Ann ArborOct11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%SepNovOct 163%Oct 163%Oct 3152%Oct 3152%Oct 1160%Oct 1160%Oct 2155%Oct 2155%clearmostly clearpartly cloudymostly cloudyovercast
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Ann Arbor, the chance of a wet day over the course of October is decreasing, starting the month at 28% and ending it at 22%.

For reference, the year's highest daily chance of a wet day is 35% on June 15, and its lowest chance is 16% on February 2.

Probability of Precipitation in October in Ann Arbor

The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

To show variation within the month and not just the monthly total, we show the rainfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day rainfall during October in Ann Arbor is decreasing, starting the month at 2.6 inches, when it rarely exceeds 4.6 inches or falls below 1.2 inches, and ending the month at 2.1 inches, when it rarely exceeds 3.5 inches or falls below 0.8 inches.

Average Monthly Rainfall in October in Ann Arbor

The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average snowfall.

Over the course of October in Ann Arbor, the length of the day is rapidly decreasing. From the start to the end of the month, the length of the day decreases by 1 hour, 22 minutes, implying an average daily decrease of 2 minutes, 43 seconds, and weekly decrease of 19 minutes, 4 seconds.

The shortest day of the month is October 31, with 10 hours, 23 minutes of daylight and the longest day is October 1, with 11 hours, 45 minutes of daylight.

Hours of Daylight and Twilight in October in Ann Arbor

Hours of Daylight and Twilight in October in Ann ArborOct11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hrSepNovnightnightdaydayOct 111 hr, 45 minOct 111 hr, 45 minOct 3110 hr, 23 minOct 3110 hr, 23 min
The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise of the month in Ann Arbor is 7:31 AM on October 1 and the latest sunrise is 35 minutes later at 8:06 AM on October 31.

The latest sunset is 7:16 PM on October 1 and the earliest sunset is 47 minutes earlier at 6:29 PM on October 31.

Daylight saving time is observed in Ann Arbor during 2023, but it neither starts nor ends during October, so the entire month is in daylight saving time.

For reference, on June 21, the longest day of the year, the Sun rises at 5:58 AM and sets 15 hours, 17 minutes later, at 9:15 PM, while on December 22, the shortest day of the year, it rises at 8:00 AM and sets 9 hours, 5 minutes later, at 5:06 PM.

Sunrise & Sunset with Twilight and Daylight Saving Time in October in Ann Arbor

Sunrise & Sunset with Twilight and Daylight Saving Time in October in Ann ArborOct11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031312 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMSepNov7:31 AM7:31 AMOct 17:16 PMOct 17:16 PM8:06 AM8:06 AMOct 316:29 PMOct 316:29 PM7:48 AM7:48 AMOct 166:51 PMOct 166:51 PMSolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day over the course of October. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray.

The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation.

Solar Elevation and Azimuth in October in Ann Arbor

Solar Elevation and Azimuth in October in Ann ArborOct112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMSepNov00101020202030405000010102020303040
northeastsouthwest
Solar elevation and azimuth over the course of October 2023. The black lines are lines of constant solar elevation (the angle of the sun above the horizon, in degrees). The background color fills indicate the azimuth (the compass bearing) of the sun. The lightly tinted areas at the boundaries of the cardinal compass points indicate the implied intermediate directions (northeast, southeast, southwest, and northwest).

The figure below presents a compact representation of key lunar data for October 2023. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.

Moon Rise, Set & Phases in October in Ann Arbor

Moon Rise, Set & Phases in October in Ann ArborOct112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMSepNovSep 149:40 PMSep 149:40 PMSep 295:58 AMSep 295:58 AMOct 141:56 PMOct 141:56 PMOct 284:25 PMOct 284:25 PMNov 134:28 AMNov 134:28 AMNov 274:17 AMNov 274:17 AM6:36 AM6:36 AM7:54 PM7:54 PM7:14 PM7:14 PM7:36 AM7:36 AM7:34 AM7:34 AM6:56 PM6:56 PM6:26 PM6:26 PM9:01 AM9:01 AM7:43 AM7:43 AM5:14 PM5:14 PM4:24 PM4:24 PM8:08 AM8:08 AM
The time in which the moon is above the horizon (light blue area), with new moons (dark gray lines) and full moons (blue lines) indicated. The shaded overlays indicate night and civil twilight.
Oct 2023IlluminationMoonriseMoonsetMoonriseMeridian PassingDistance
1
95%-10:11 AMWNW8:28 PMENE3:02 AMS229,082 mi
2
89%-11:27 AMWNW8:59 PMENE3:53 AMS232,599 mi
3
81%-12:41 PMNW9:36 PMNE4:46 AMS236,478 mi
4
71%-1:50 PMNW10:21 PMNE5:40 AMS240,378 mi
5
61%-2:50 PMNW11:14 PMNE6:35 AMS243,987 mi
6
50%-3:40 PMNW-7:28 AMS247,060 mi
7
41%12:13 AMNE4:20 PMNW-8:20 AMS249,432 mi
8
31%1:16 AMNE4:52 PMWNW-9:08 AMS251,018 mi
9
23%2:20 AMENE5:19 PMWNW-9:54 AMS251,808 mi
10
15%3:24 AMENE5:41 PMWNW-10:36 AMS251,854 mi
11
9%4:26 AMENE6:00 PMW-11:17 AMS251,250 mi
12
4%5:28 AME6:19 PMW-11:56 AMS250,115 mi
13
1%6:31 AME6:37 PMW-12:36 PMS248,577 mi
14
0%7:34 AME6:56 PMWSW-1:16 PMS246,757 mi
15
1%8:39 AMESE7:17 PMWSW-1:59 PMS244,754 mi
16
4%9:47 AMESE7:43 PMWSW-2:45 PMS242,643 mi
17
10%10:57 AMESE8:14 PMWSW-3:35 PMS240,469 mi
18
17%12:08 PMSE8:53 PMSW-4:31 PMS238,258 mi
19
26%1:16 PMSE9:44 PMSW-5:30 PMS236,031 mi
20
37%2:17 PMSE10:46 PMSW-6:32 PMS233,823 mi
21
50%3:09 PMSE11:58 PMSW-7:34 PMS231,701 mi
22
60%3:50 PMESE--8:33 PMS229,772 mi
23
71%-1:16 AMWSW4:23 PMESE9:29 PMS228,185 mi
24
82%-2:35 AMWSW4:51 PMESE10:21 PMS227,111 mi
25
90%-3:53 AMWSW5:15 PME11:11 PMS226,723 mi
26
96%-5:10 AMW5:38 PME11:59 PMS227,152 mi
27
98%-6:26 AMW6:01 PME--
28
100%-7:43 AMWNW6:26 PMENE12:48 AMS228,459 mi
29
100%-9:01 AMWNW6:55 PMENE1:38 AMS230,608 mi
30
97%-10:17 AMWNW7:29 PMNE2:31 AMS233,456 mi
31
93%-11:30 AMNW8:11 PMNE3:25 AMS236,774 mi

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

The chance that a given day will be muggy in Ann Arbor is gradually decreasing during October, falling from 3% to 0% over the course of the month.

For reference, on August 1, the muggiest day of the year, there are muggy conditions 34% of the time, while on January 1, the least muggy day of the year, there are muggy conditions 0% of the time.

Humidity Comfort Levels in October in Ann Arbor

Humidity Comfort Levels in October in Ann ArborOct11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%SepNovOct 13%Oct 13%Oct 310%Oct 310%Oct 111%Oct 111%Oct 210%Oct 210%muggymuggyhumidhumiddrydrycomfortablecomfortable
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The percentage of time spent at various humidity comfort levels, categorized by dew point.

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in Ann Arbor is increasing during October, increasing from 10.0 miles per hour to 11.2 miles per hour over the course of the month.

For reference, on January 15, the windiest day of the year, the daily average wind speed is 12.8 miles per hour, while on August 4, the calmest day of the year, the daily average wind speed is 7.9 miles per hour.

Average Wind Speed in October in Ann Arbor

The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The hourly average wind direction in Ann Arbor throughout October is predominantly from the west, with a peak proportion of 38% on October 30.

Wind Direction in October in Ann Arbor

Wind Direction in October in Ann ArborSWOct11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%20%80%40%60%60%40%80%20%100%0%SepNovwestsouthnortheast
northeastsouthwest
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Ann Arbor is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.

The average surface water temperature in Ann Arbor is rapidly decreasing during October, falling by 11°F, from 64°F to 53°F, over the course of the month.

Average Water Temperature in October in Ann Arbor

Average Water Temperature in October in Ann ArborOct112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313135°F35°F40°F40°F45°F45°F50°F50°F55°F55°F60°F60°F65°F65°F70°F70°F75°F75°F80°F80°FSepNovOct 164°FOct 164°FOct 3153°FOct 3153°FOct 1160°FOct 1160°FOct 2157°FOct 2157°F
The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

The growing season in Ann Arbor typically lasts for 5.7 months (173 days), from around April 25 to around October 15, rarely starting before April 8 or after May 13, and rarely ending before September 26 or after November 2.

During October in Ann Arbor, the chance that a given day is within the growing season is very rapidly decreasing falling from 82% to 13% over the course of the month.

Time Spent in Various Temperature Bands and the Growing Season in October in Ann Arbor

Time Spent in Various Temperature Bands and the Growing Season in October in Ann Arborgrowing seasonOct11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%SepNov82%Oct 182%Oct 1Oct 3113%Oct 3113%60%Oct 1160%Oct 11Oct 2134%Oct 2134%freezingvery coldcoldcoolcomfortablewarm
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The percentage of time spent in various temperature bands. The black line is the percentage chance that a given day is within the growing season.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

The average accumulated growing degree days in Ann Arbor are gradually increasing during October, increasing by 148°F, from 2,783°F to 2,930°F, over the course of the month.

Growing Degree Days in October in Ann Arbor

Growing Degree Days in October in Ann ArborOct11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031312,600°F2,600°F2,700°F2,700°F2,800°F2,800°F2,900°F2,900°F3,000°F3,000°F3,100°F3,100°F3,200°F3,200°FSepNovOct 12,783°FOct 12,783°FOct 312,930°FOct 312,930°FOct 162,878°FOct 162,878°F
The average growing degree days accumulated over the course of October, with 25th to 75th and 10th to 90th percentile bands.

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy in Ann Arbor is rapidly decreasing during October, falling by 1.5 kWh, from 4.2 kWh to 2.7 kWh, over the course of the month.

Average Daily Incident Shortwave Solar Energy in October in Ann Arbor

Average Daily Incident Shortwave Solar Energy in October in Ann ArborOct11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWhSepNovOct 14.2 kWhOct 14.2 kWhOct 312.7 kWhOct 312.7 kWhOct 163.4 kWhOct 163.4 kWh
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

For the purposes of this report, the geographical coordinates of Ann Arbor are 42.278 deg latitude, -83.741 deg longitude, and 873 ft elevation.

The topography within 2 miles of Ann Arbor contains only modest variations in elevation, with a maximum elevation change of 243 feet and an average elevation above sea level of 861 feet. Within 10 miles also contains only modest variations in elevation (384 feet). Within 50 miles contains only modest variations in elevation (801 feet).

The area within 2 miles of Ann Arbor is covered by artificial surfaces (98%), within 10 miles by cropland (51%) and artificial surfaces (30%), and within 50 miles by cropland (49%) and artificial surfaces (24%).

This report illustrates the typical weather in Ann Arbor, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.

Temperature and Dew Point

There are 5 weather stations near enough to contribute to our estimation of the temperature and dew point in Ann Arbor.

For each station, the records are corrected for the elevation difference between that station and Ann Arbor according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.

The estimated value at Ann Arbor is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Ann Arbor and a given station.

The stations contributing to this reconstruction are:

To get a sense of how much these sources agree with each other, you can view a comparison of Ann Arbor and the stations that contribute to our estimates of its temperature history and climate. Please note that each source's contribution is adjusted for elevation and the relative change present in the MERRA-2 data.

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , by Jean Meeus.

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for airports and weather stations are provided by AskGeo.com .

Maps are © OpenStreetMap contributors.

Disclaimer

The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.

We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.

Please review our full terms contained on our Terms of Service page.