| Temperatures | Precipitation | ||||||
| Month | High | Low | Average | Departure | Total | Departure | Snow |
| January | 24.2 | 9.6 | 16.9 | +1.2 | 0.62 | -0.24 | 10.0 |
| February | 17.1 | -1.6 | 7.8 | -12.5 | 0.65 | -0.18 | 10.6 |
| March | 42.0 | 22.9 | 32.5 | +0.1 | 1.07 | -0.81 | 10.9 |
| April | 58.3 | 37.1 | 47.7 | +1.0 | 4.93 | +1.69 | 1.5 |
| May | 67.0 | 48.4 | 57.7 | -0.4 | 5.25 | +1.62 | 0.0 |
| June | 77.2 | 57.4 | 67.3 | -0.3 | 4.46 | -0.22 | ... |
| July | 79.4 | 59.6 | 69.5 | -1.9 | 4.94 | +0.39 | ... |
| August | 75.9 | 57.2 | 66.5 | -2.6 | 3.16 | -1.36 | ... |
| September | 76.3 | 56.1 | 66.2 | +5.3 | 2.88 | -0.57 | ... |
| October | 60.9 | 40.0 | 50.5 | +2.1 | 1.26 | -0.98 | 0.2 |
| November | 47.8 | 30.9 | 39.3 | +5.5 | 3.08 | +1.17 | 2.3 |
| December | 34.9 | 24.8 | 29.8 | +10.1 | 3.21 | +1.98 | 13.2 |
| TOTALS: | 55.1 | 36.7 | 46.0 | +0.6 | 35.51 | +2.49 | *** |
Records
Temperature...
Highs:
93 on June 9th, tied with previous years
84 on October 11th
Lows:
Highest Lows:
Lowest Highs:
Monthly:
Seasonal:
Yearly:
Precipitation...
One-day pcpn:
One-day snowfall:
Monthly pcpn:
Monthly snowfall:
Seasonal precipitation:
Yearly precipitation:
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Unlike the previous year, 2015 did not get off to a frigid start. Aside from a 10 day stretch with below normal temperatures (4th through 13th), January was relatively mild. Highs were above freezing 9 days (average is 7) with lows under 20 degrees 19 times (average is 25) – tied for 7th least in a January. It was a dry month, receiving only 60% of the January normal. Measurable snow fell on 9 days – right around normal – but only amounted to 9.4 inches. In addition, daily amounts held under 2 inches for the entire month. This occurs less than 2 out of every 10 years. addition, daily amounts held under 2 inches for the entire month. This occurs less than 2 out of every 10 years. |
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The icebox returned in February with an average temperature over 12 degrees below normal, making it the 5th coldest February on record. Lows dropped below zero on 15 days, well above the average of 8 days and tying it for 7th most in a February. Highs held in the single digits 9 times (never getting above zero on the 18th) and only warmed above freezing on 3 days. The 10.6 inch snow total was about 2 inches above normal. There were 7 days with measurable snowfall
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By its own standards, March’s average temperature was normal. However, there were significant swings day to day, week to week. Rochester had a high of only 9 degrees on the 5th, yet would warm to 62 by the 13th. That 9 degree day was only the 23rd time on record that a March day failed to warm to 10 or better. To further illustrate the roller coaster that was March, highs warmed to 60 or higher on 5 days, but failed to warm above freezing on 7 days. March looked like it might be a very dry month with only one day of accumulating precipitation – for only a mere 0.3 inches of snow - through the 21st. Snow then fell on 4 consecutive days, with the bulk of the month’s 10.9 inch total falling on the 22nd (7.4” – tied for 15th snowiest March day on record). The 10 inch snow depth on the morning of the 25th did not stick around long, melting away by the 30th. |
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Typical for a spring month, April experienced the wild swings in temperature that occurred in March. There were more days with highs in the 40s and 50s (13) than in the 70s and 80s (10). Ironically, the 82 degree high for the month came on the 1st. It was also well ahead of the normal first 80 degree day in a year (April 29th). Over 4 inches of precipitation fell in April, almost 1 ½ inches above normal. However, nearly 2/3rds of that total came on the 7th and 9th, with only around an inch then falling through the end of the month. April did squeeze out some more snow though with minor accumulations on the 9th and 22nd (total of ½ inch for month). |
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Not much consistency in temperatures for May either, although it did manage to finish above normal. Highs warmed to 80 degrees or higher 10 times, but couldn’t manage to get out of the 50s and 60s on 12 days. The wet trend would continue, but a bit more spread out compared to April. Measureable rain fell on 16 days, with 5 of those recording over 3/4rds of an inch. The 6.41 inch monthly total made it the 12th wettest May on record. On the whole, March, April and May would finish amongst the top 20 spring’s for temperature and precipitation (17th warmest and 18th wettest respectively). |
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June was around normal for temperatures and a bit below in terms of rainfall. The warmest temperature of the year occurred on the 9th with a high of 96 degrees. However, it would be the only time it warmed into the 90s all month. Ironically, the coldest high occurred just a couple days later – 66 degrees on the 11th. Even though precipitation was below normal, what fell was spread across June, with no more than 4 days between accumulating rainfall. |
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July got off to a relatively cool start with below normal temperatures on 10 of the first 11 days. Summery conditions settled in after that with highs 82 degrees or warmer from the 17th through month’s end. Rainfall was below normal for the second straight month – and got off to a very dry start. There was only 1 day of accumulating rainfall through the 12th with 0.40 inches dropping on the 6th. After that though, rain came on a fairly regular basis, falling every few days
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August continued the cool trend, finishing around 2 ½ degrees below normal. Temperatures were below normal on nearly 2 out or every 3 days with highs failing to warm out of the 60s on 5 days. August was dry compared to its normal, with the first 2 weeks responsible for much of the deficit. Measurable rain fell on only 2 days during the first 15 days, amounting to a mere 0.06 inches.
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September started very warm as highs topped out in the 80s the first 6 days. It was the third warmest start to a September in Rochester, averaging 76.8 degrees during that period (1960 was the warmest at 81.3 degrees). Aside from a few cooler days at mid-month and right at the end, it would stay warm and finish as the 2nd warmest September on record at 66.2 degrees. Highs were 80 degrees or higher 10 times - average is 7. In addition, highs only failed to crack 70 six times, below the average of 13 and tied for 4th fewest. Interestingly, there were no record high temperatures for the month, and only two highest lows. September was below normal for precipitation, with most of it falling in the first half of the month. After the 17th, there were only two days with measurable rain, and those only amounted to 0.06 inches. |
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While October would finish above normal for temperatures, there was quite a bit of fluctuation. For example, it was 84 degrees on the 11th, the high for the month and the last 80 plus degree day of 2015. Just two days later, the high was only 60. The first freezing temperature of the fall season came on the morning of the 16th with 27 degrees. This was over two weeks later than average. The dry trend of late September persisted into October with only one day of accumulating rainfall through the 22nd, and that was only 0.01 inches on the 8th. It tied for the 4th driest start to an October on record. The last 9 days would try to make up for this deficit, raining on 7 of those for almost the entire 1.26 inch October total. This late burst helped, but still kept it about an inch below normal. |
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November continued the warm conditions of September and helped round out the fall months as the 2nd warmest on record at 52.0 degrees. It was the 6th warmest November at 39.3 degrees. At or above normal temperatures occurred on all but 6 days in November…with the warmest stretch during the first 2 plus weeks of the month. Low temperatures at or below freezing only occurred on 16 days…tied for fourth least in a November…and well below the average of 24 such days. Precipitation was above normal for the month. The bulk came at mid-month with over 70 percent falling between the 11th and the 20th. The first measurable snow fell in November with 1.3 inches on the 20th. This is over two weeks later than the average first measurable now in Rochester /Nov 5th/. |
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December rounded out 2015 very mild and wet, setting records for both. Daily temperatures were above normal on all but 3 days with highs reaching or exceeding 40 degrees on 13 days (average is only 4). The average low temperature of 24.8 degrees was only 2.3 degrees off the normal average high temperature for December. Lows only dropped into the single digits 3 times – tied for 5th least in a December and well below the average of 13. The mild temperatures kept much of December’s precipitation as rain, with the total of 3.21 inches making it the 2nd wettest on record. Less than 2 inches of snow fell through the 22nd , but almost 4 inches would fall on the 23rd with another 8.5 inches coming on the 28th and 29th. The late month dumping brought the total for the month above its normal. |
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2015 will be remembered more for how it ended rather than started. A strong El Nino played a significant role in making it very mild. The last 4 months of the year were the 2nd warmest on record for Rochester. The only month of the four to not set a top 10 record was October. Seven of the months of 2015 were above normal, with the only significantly cold month coming in February. While the year finished above normal for precipitation, much of that was due to a wet spring and rainy early start to the winter. |
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| Highest temperature for 2015 | 93 on June 9th |
| Lowest temperature for 2015 | -17 on Jan 13th and Feb 5th |
| Highest one-day precipitation | 1.67 inches on July 28th |
| Highest one-day snowfall | 7.4 inches on March 22nd |
| Number of days with highs at or above 90 degrees | 1 |
| Number of days with highs at or below 32 degrees | 70 |
| Number of days with zero or below temperatures | 27 |
| Peak wind gust | 56 mph from the SE on May 6th |
| Number of days with measurable precipitation | 119 |
| Percentage of days with measurable precipitation | 33% |
| Number of days with above normal temperatures | 208 |
| Percentage of days with above normal temperatures | 57% |
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