With a lack of rainfall, unusually low humidity, and an abundance of sunny pleasant days, the majority of May's days were optimal for outside activities. The month did come in cooler than average by 0.8 degrees at Albany, the first cooler than average month since June 2022. But the perception for most was that May was mild. And since more days came in with high temperatures that were warmer than average versus cooler than average, that makes sense. May's cold bias came at night with most nights coming in with below average low temperatures. This was due largely to numerous clear nights coupled with the prevalence of dry air which lead to frequent optimal radiational cooling conditions and subsequent big temperature drops. In fact five days at Albany came in with a minimum temperature that fell into the 30s with an unusually cold morning on the 18th which resulted in widespread frost and freezing conditions with vegetation damage reported in a number of locations.

Month Highlights

• Cooler than average - monthly mean temperature of 58.8 degrees (-0.8)
• Daytime high temperatures averaged 1.4 degrees warmer than normal
• Daily low temperatures averaged 2.9 degrees cooler than average
• One 90 temperature on the 28th
• Tied with May 1862 for 9th driest May on record to date: 1.16" of rain (-2.25")
• Only 6 days at Albany with measurable rainfall
• An atypically large number of bright sunny days
• Unusually dry air through the month with dewpoints on most days in the 30s and 40s
• Numerous days between the 9th and 31st with elevated Canadian wildfire smoke causing "Hazy" skies
• No thunderstorms
• Peak wind gust from the west of 41 mph on the 1st

THE PATTERN AND WILDFIRE SMOKE

The first couple of days of May were cloudy, damp, and chilly with a lingering omega block pattern at the jet stream level which began in April which featured a chilly low pressure trough aloft over the Northeast. Of the six days in May with measurable rainfall at Albany, three of them happened from the 1st through the 3rd.

The omega block pattern broke down by the 4th with a new blocking pattern aloft forming which featured strong high pressure ridging over Canada and the U.S. northern tier which kicked the low pressure trough out of the Northeast and put the local area in a prolonged dry northwest flow through much of the month.

The ridge aloft created unusually hot and dry weather over especially western Canada which enhanced existing warm and dry conditions there which supported a high number of wildfires over especially Alberta. That wildfire smoke was captured by the jet stream and frequently blown over the Northeast creating hazy skies over the region between the 8th and the 23rd. Fortunately there were no air quality issues as the particulate matter was high up in the atmosphere not near the ground.

A rex block at the jet stream level developed during the final two weeks of the month with a strong high pressure center aloft over the Midwest and Northeast on top of a cut-off upper low over the southern states. That set-up lead to a cloudy, wet, and cold Memorial Day weekend for much of the Southeast, but a hot and dry one locally. Wildfires in Nova Scotia then erupted with smoke from those blazes transported into the Northeast between the 28th and 31st on a lower level easterly flow that set-up around a surface high located over southeast Canada. Once again hazy skies occurred with the particulate matter in low enough concentration not to create any air quality issues.

With so much jet stream blocking through the month and the subsequent stability of the pattern that set-up there were not any major temperature swings from hot to cold. The daily mean temperature departure graph shows rather modest ups and downs with the two day cold period from the 17th-18th evident as well as the very warm last four days of the month. (A daily mean temperature is calculated by adding the daytime high temperature and low temperature then dividing by 2)

Cooler than average conditions for May were also observed at the four other local climate reporting sites

RAINFALL

With the stable and very persistent dry northwest flow pattern through the month, it's not a surprise that there wasn't much rain, although it was a little more generous across the mid Hudson valley and western New England than across the rest of the region due to a passing storm on the 20th. Only 1.16" of rain fell at Albany which was 2.25" below the 1991-2020 thirty year average and tied with May 1862 for 9th driest on record to date. There were only six days at Albany where measurable rain fell. By the end of the month lawns across much of the region were dry and brown, more like one would expect in July or August rather than at the end of May.

Despite the persistent dryness in May, a wet March and April balanced out the deficit yielding an average spring overall for precipitation. This is why the Northeast drought monitor only showed some patchy areas of abnormally dry developing across the region versus drought conditions. Water supplies by the close of the month were fine, but surface dryness was extensive.

May 2023 rainfall amounts for the local climate sites

• Glens Falls
  1.64" (-1.71")
• Poughkeepsie
  0.97" (-2.50")
• Bennington, VT
  Missing due to ongoing instrument issues
• Pittsfield, MA
  2.18" (-1.61")

METEOROLOGICAL SPRING 2023 SUMMARY - March, April, May

Compared to the 1991-2020 30 Year Climate Normals

Quick Summary

• Warmer Than Average
• Average Precipitation
• Above Average Snowfall

There were more warmer than average days than cooler than average days at Albany over the three month spring period of March, April, and May. The season averaged out warmer than average because the warm days in many instances were quite warm with many of the cooler than average days only slightly below average.

This is the third spring being compared to the new 1991-2020 30 year "Climate Normals" data set which are warmer, wetter, and slightly less snowy than the previous 1981-2010 data set. With the warmer baseline now in use to make comparisons, meteorological spring 2023 still averaged out warmer than the new normal at all the local climate sites. The graphic below shows the three month mean temperatures and departures for the five local climate reporting stations.

Spring Highlights

• Strongest wind Gust: 48 mph from the NW on March 29
• 2 T'Storm Days
• Last 32 degree or lower day at Albany was May 18
• Lowest temperature at Albany: 20 degrees on March 1
• Highest temperature at Albany: 90 degrees on May 28
• 2 Days with precipitation of 1.00" or greater

For a detailed look at the weather in April 2023, click here: "April 2023 was Noteworthy for Unusual Warmth - Here's How The Month Went Down"

For a detailed look at the weather in March 2023, click here: "March 2023 - Not Cold, But It Was Snowy - Here's the Wrap"