2021 was a HOT one. Not just hot by summer standards, but historically: it was our 5th warmest year ever recorded. Let's take a look at some of the most significant weather/climate events by each month! (To read about the significance of the year overall being the 5th warmest I break that down HERE).

2021 overall temperature anomalies (difference from the 30-year, 1991-2020 normal):

JANUARY 2021:

January was a VERY mild month. It was our 12th warmest on record. The notable thing of the month was that we NEVER dropped below zero! It was only the third time to do so (1990, 2006, and 2021). What was odd though, was the CONSISTENT warmth. In other words: we didn't have extreme warm days of (40s or 50s) but rather, most days were in the 30s. Bizarrely the warmest temperature was 'only' 39°. Maybe that doesn't sound like a big deal, but, on AVERAGE we should hit 40° twice in a NORMAL January. So, to be the 12th warmest and not hit 40° once is yet another alarm bell of a warm January caused almost solely by climate change. It's about the consistent warmth, the warmth that lingers around. Warm nights and moderately warm days. That's what a greenhouse is: it traps heat rather than creates extremes.

February 2021:

Of course February will be remembered as the one & only cool month of the year. It was notable in the deep freeze that hit Texas. Indeed, Minnesota 'suffered' an extended outbreak of cold. It broke almost NO records (in Minnesota), but did match some records in terms of length of cold. The cold snap averaged about 20° below normal for a two week period, enough to make it a cold February, well below normal (using the 1991-2020 averages).

March 2021:

Was yet another mild, uneventful month. That's saying a lot. March is often a turbulent battle between winter & spring & can often bring some fierce snow storms & first warmth of spring. Instead, it was very mild and almost snow-less. It was our 8th warmest March ever recorded. We only saw 4" of snow, half our normal amount. It was notable in seeing our first 70°+ reading of 73° on March 29th. This was about a full week earlier than the normal.

April 2021:

April & May both were bizarre months of extremes. We saw the warmest first week of April ever recorded with a peak high temperature of 85° on April 5th- the warmest it had been that warm, that early. Was the a harbinger of things to come? It would turn out to be in June. We went from that extreme, early warmth to a two week period of relative cold that took what would have been a record April to nearly normal by month's end.

May 2021:

Was much like April, cold spells but with almost record warmth that all balanced out to a nearly normal month, when averaged out. We started the month at 87° on May 1st and fell to a low of 36° 10 days later. This is why I think Spring is so exciting (but it can be torture in Minnesota!). By later in the month, we were again at 87° on May 24th. That kind of warmth only happens once in an average May, so, to do it twice was significant. Still the month ended just 0.5° above normal.

June 2021:

This is THE month of note to me as a meteorologist & climate observer. It was a month of so many HOT extremes. Extremes mean more when they're at the extreme part of the year (be it the hottest time of year or coldest). June was our second hottest ever, but the most notable event was that we saw a kind of heat never seen that early in a summer.

Take for example July 1988 or 1936: two of our hottest Julys. The had normal ups & downs combined with extreme warmth (100°+), that 'averaged out' more or less. This June was hotter than an average July and was the hottest month of year. We had 9 consecutive days of 90°+ from June 3-June 11: the earliest streak of such weather and tied for the 3rd most ever. In fact, only 8 other times on record have we had that kind of streak of consecutive heat.

July 2021:

Many were dreading the possibility of what might happen in July, it being our hottest month (normally) but July ended up being more tame than June. It ended up being just slightly above normal at +0.6° F (the 33rd warmest out of 148 years). The bigger story in July was the ongoing drought increasing in severity. We saw just 21% of our normal precipitation in July. Severe & extreme drought expanded on the drought monitor across the state.

August 2021:

August saw the temperature anomaly (difference from normal) increase again. The month was +2.2°F above normal (17th warmest out of 148 years). The bigger story was almost miracle-like rains that came August 7th-8th and again August 24th-26th: a combined 4.95" just on those dates. August rainfall in total came to a whopping 6.88": that was nearly 2.5 times more than all of June & July combined!

September 2021:

September saw things heat up again (relative to normal, not in 'absolute' terms). The temperature anomaly was a full +3.0° F above normal, making it the 16th warmest (of 148 years). While August looked promising at putting a big dent in the drought, suddenly, the rains stopped after Labor Day making for a dry period again that would continue into October. We hit 90° on the 19th: pretty late in the season for that feat. August 25th is the normal date of the last 90°. It was only the fourth time in 25 years to have that kind of heat that late.

October 2021:

October was another game-changer for heat (again, relative to normal). The first 11 days of the month were consecutively at or above 70°: one of the longest stretches ever, that late. We weren't done with the heat after that either. On October 18th & 19th we again soared into the 70s, almost near 80° on the 18th (the high was 79°). The heat in October pushed us to the 9th warmest ever recorded. The temperature anomaly was a whopping +6.1° F above normal. It also continued to be a pretty dry month.

November 2021:

November was pretty uneventful. It was mild overall, but modestly so compared to the two previous months. It was +1.6° F above normal. We saw our first snowfall finally on the 13th (just 1.2"). That would be IT for measurable snowfall for the month though. The normal snowfall in November is 6.8", so we started our season well behind.

December 2021:

If I had to pick one or two months to REALLY stand out in what was already a stand-out crazy year for weather/climate, December & June would be my top picks. June was hot (2nd hottest) & saw our earliest extreme/consecutive heat, but December had extreme heat and an extreme confluence of not one but several rare events come together to produce a never before recorded event: TORNADOES in a winter month!

Making it all the more bizarre, we had 11.8" of snow Dec. 10-11, that then all melted and produced a record-high temperature of 58° on December 15th. As close as La Crosse, WI was almost 70° (*topped out at 69°).

The very rare list of events were:

* Unusually LOW pressure coming out of the rockies creating a freak wind storm of over 100mph in Colorado and wind gusts (separate from thunderstorms) in Minnesota that also were over 60mph.

* Record warm air for that time of year (this would be notable enough)

* Record high moisture: dew points were in the 50s with a places near 60° in southern Minnesota. That is off- the - charts high for December and likely broke many records.

All of these combined to produce a never before seen severe weather outbreak that produced more than a dozen tornadoes. Minnesota had NEVER had a tornado recorded in December before (nor in any winter month of December, January, February).

The Twin Cities National Weather Service has a great write up on the days events & damage reports HERE.

All and all it was a historic year with several historic, notable weather & climate events contained within it. If you missed my previous article on the significance of 2021 overall being the 5th warmest, check it out HERE.

-Meteorologist Sven Sundgaard