Records

Temperature...

Highs:

• 61 on March 9th
• 81 on April 4th
• 91 on May 1st
• 93 on June 4th, tied previous years
• 95 on June 5th
• 64 on December 15th, also tied for all-time warmest December day
• 41 on December 24th, tied previous years

Lows:

• -23 on February 15th

Highest Lows:

• 56 on April 6th
• 69 on June 5th, tied previous years
• 68 on June 6th, tied previous years
• 69 on June 9th, tied previous years
• 69 on June 10th, tied previous years
• 71 on June 11th, tied previous years
• 37 on December 15th, tied previous years

Lowest Highs:

• -6 on February 12th
• -3 on February 13th
• -8 on February 14th

Monthly:

• 6th coldest February at 8.3 degrees, tied with 1978
• 10th warmest March at 38.0 degrees
• 2nd warmest June at 73.0 degrees

Seasonal:

• 8th warmest summer at 71.2 degrees
• 6th warmest fall at 50.7 degrees, tied previous years

Yearly:

• 7th warmest at 46.8 degrees

Precipitation...

One-day pcpn:

• 1.33” on July 6th
• 3.51” on August 27th
• 0.68” on October 28th

One-day snowfall:

• 7.9” on March 15th
• 6.5” on December 10th

Monthly pcpn:

• 4th driest April with 0.81”
• 7th driest June with 1.46”
• 7th wettest August with 6.74”

Monthly snowfall:

• None

Seasonal precipitation:

• None

Yearly precipitation:

• None

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  January got 2021 started off on a mild note with above normal temperatures on 17 of the first 18 days. That mild stretch of days was the 3rd warmest start on record (1st through the 18th) for January in Rochester. Temps took a tumble after that with below normal temperatures on 7 out of the next 10 days. The last few days would rebound to the mild conditions that the month started on. Low temperatures fell below zero on 4 days, well below the average of 12 such days and tied for 8th least in a January. Precipitation and snowfall was close to the normal for January.  There wasn’t any measurable snow for almost the first 2 weeks of the new year, with 4.1 inches finally falling on the 14th. After that, there would be periodic snowfalls with daily amounts mostly holding under 2 inches.
  The mild end of January persisted into February until a winter storm plowed through the region on the 4th. After that, temperatures took a significant dive with arctic air funneling southward and then holding across the Upper Mississippi River Valley through mid month. Below normal temperatures were recorded from the 5th through 20th. It was so cold that highs never warmed above zero from the 11th through the 15th. Below zero lows occurred on 14 days, almost double the average of 8. Further, lows bottomed out from -10 and colder on 11 days, tied for 2nd most in a February. The thermostat would be cranked up for the last week of February with temps topping out in the upper 30s and lows mostly near 20. On the whole, February averaged 8.3 degrees which was 12 degrees below normal and tied it for 6th coldest February on record. Snowfall for the month was a couple inches below normal, with the bulk of that coming on 2 days (3.0” on the 4th and 4.6” on the 21st). There were only 4 other days with measurable snow and all were under ½:”
  February’s mild end would persist for most of March, with only 6 days of below normal temperatures. The first 60 degree day of the year came on the 9th, a few weeks early compared to the average. Despite averaging over 5 ½ degrees above normal, there was significant fluctuation in temps with highs ranging from 21 on the 1st to 68 on the 29th. All said, March would finish as the 10th warmest on record in Rochester. Precipitation and snow were right around normal. However, one day accounted for nearly the entire month’s snowfall with 7.9” on the 15th. There were only 2 more days with measurable snow, and those were the following two days with less than ¼” on each of them. That snowfall on the 17th would be the last measurable snow for the 2020-21 season, several weeks earlier than the average (April 10th).
  April saw its share of ups and downs when it came to temperatures, with a high of 42 on the first quickly reaching 81 on the 4th. This 80 degree temperature was a month earlier than normal and 3rd earliest 80 day on record for Rochester. Highs would warm to 70 degrees or greater 5 times, but couldn’t crack 50 degrees on 11 days. Despite the swings in temperatures, April would finish right around its normal. Precipitation was fairly sparse with measurable precipitation on only 7 days (average is 11). The 9th accounted for half of the monthly total with mostly under 1/10” on the other days. The monthly total of 0.81” made it the 4th driest April on record in Rochester. The last flurries for the season fell on the 25th.
  May was another month with wide fluctuations in temperature, which should be expected for a spring transitional month. Summer lovers were likely overjoyed with the 91 degree day to kick off the month. That is over 5 weeks sooner than the average first 90 degree day and 4th fastest in a year for Rochester. That taste of summer would be short-lived as highs would tumble back into the 50s and 60s after that. Temperatures would still manage to push past 80 degrees on 3 days for the month. On the whole, all the fluctuations averaged out right at the May normal. Rainfall was also close to what is expected in May, but went it fell, it was feast or famine. Out of the 13 days with measurable precipitation, 5 of those recorded around ½” or greater.  The other 8 days were generally around 1/10” or less.
  June was a very warm month, hot by some standards. High temperatures reached or exceeded 90 9 times, tied for 7th most in a June and blew away the average of 3. In fact, it was just one under what occurs on average over an entire year. Highs touched 95 twice (the 5th and 10th) and was the warmest temperature in Rochester for 2021. Most of the warmth came during the first half of the month. The average temperature through the first 2 weeks was 76.0 degrees making it the warmest start to a June on record. Interestingly, during most of the streak humidity was relatively low, which resulted in heat indices not much higher than the temperature. In addition, low temps for the month only cooled into the upper 60s or warmer on 11 days – tied for most in a June. Overall, the monthly average of 73.0 made it the 2nd warmest June on record for Rochester. With the warmth came dry conditions. The first rain didn’t fall until the 17th, with only 5 days total of measurable rains (tied for 6th least in a June).  The monthly total of 1.46” was the 7th driest for a June.
  Temperatures were fairly typical for July with daily averages generally staying within a few degrees of the normal. After the string of 90 degree days in June, it would only reach that number once in July. In addition, temps failed to reach 70 on 7th.  Overall, the month rounded out a degree above normal. July finished right around the normal for rainfall with measurable rain falling on 10 days. However, 4 of those days accounted for over 80% of the 4.21” monthly total (6th, 7th, 14th and 27th).
  Summer warmth continued in August with daily temperatures, again, hovering around normal. August would try to make up for the dry start to the summer with its 6.74” total making it the 7th wettest August on record for Rochester.  There were 13 days with measurable rainfall with 5 of those recording ½” or greater. That said, one day would account for half of the monthly total with 3.51” falling on the 27th. Buoyed by the warmth of June, the summer averaged 71.2 degrees in Rochester, marking it as the 8th warmest on record.
  September was mild by its standards, averaging 2 degrees above normal. However, much of that was thanks to a warm end to the month. From the 26th through the 30th highs warmed into the mid 80s on 3 days while the average for that 5 day period was the 2nd warmest finish to a September on record (66.9 F). After a wet August, September dried out. There were 7 days with measurable rainfall, but 5 of those recorded less than 1/10 of an inch. In fact, the 1.05” of rain on the 3rd amounted to over 60% of the monthly total.
  Mild fall weather settled in for the first 3 weeks of October with above normal temperatures through the 20th. This 20 day stretch to start October averaged 59.1 degrees and was the 3rd warmest of its kind on record for Rochester. Temperatures would drop back to more seasonable levels on the 21st, holding for the rest of the month. The last 80 degree of 2021 came on the 1st (83 F). Meanwhile, the first freeze of the fall season didn’t come until the 21st (32 F), about 3 weeks later than normal and tied for 4th latest occurrence. Overall, the average temp for the month of 53.4 degrees was 5 ½ degrees above normal and narrowly missed finishing in the top 10 warmest Octobers in Rochester (11th). The dry fall continued with just over 1 ½ inches falling for October. The meager total was spread out across 10 days with less than 1/10” of an inch falling on 5 of those.
  November continued the mild conditions averaging around 2 degrees above normal, with a 3 day streak of highs in the 60s (6th-8th) helping with that. Precipitation in November was right on its normal, but nearly the entire 1.89” total came on 4 consecutive days at mid month (10th through the 13th). The first snow of the young winter season fell on the 12th with 0.3”, about a week later than average. Overall, the fall months of September, October and November averaged 50.7 degrees and tied it for the 6th warmest fall on record for Rochester.
  December continued the streak of warm months that started in the summer, rounding out around 4 degrees above normal. The highlight was a 49 degree day on the15th which not only set a daily record, but also tied the all-time record for any day in December. This day also saw a rare round of severe weather for December, along with widespread strong winds. In fact, the strongest wind of 2021 occurred on the 15th with a line of severe storms, hitting 77 mph from the south. There were 7 days with measurable snow recording 13.1”, about an inch above a typical December. Half of that came on the 10th when 6.5” fell. Mid month was fairly quiet for snow, only recording 0.2” from the 12th through the 25th.
  2021 will be remembered as a very warm year for Rochester. Its 46.8 degree average made it the 7th warmest on record, highlighted by the very warm June. 2021 might have been even warmer if not for the chilly February. Precipitation was the opposite for Rochester as the total for the year of 27.67” was 7 inches below normal and first time since 2012 that at least 30 inches did not fall.  Most months were at or well below their normal for precipitation except August which finished well above. In fact, more precipitation fell in August then in the following 4 months combined.

   

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  Highest temperature for 2021	95 on June 5th and 10th
  Lowest temperature for 2021	-23  on February 15th
  Highest one-day precipitation	3.51" on August 27th
  Highest one-day snowfall	7.9" on March 15th
  Number of days with highs at or above 90 degrees	11
  Number of days with highs at or below 32 degrees	65
  Number of days with zero or below temperatures	19
  Peak wind gust	77 mph from the S on Dec 15th
  Number of days with measurable precipitation	102
  Percentage of days with measurable precipitation	28%
  Number of days with above normal temperatures	207
  Percentage of days with above normal temperatures	57%