What do you consider “Early Spring temperatures”...and "Late Spring temperatures"? (averages, frost)

[Infamous92]

Originally Posted by Ariete

We use the same criteria, I made a thread about it, and was a bit surprised that very few countries do this. Our meteorological seasons are:
spring = begins when the 24h mean temp is above 0C/32F for seven consecutive days
summer = begins when the 24h mean temp is above 10C/50F for 7 days
autumn = begins after 7 days of a 24h mean temp less than 10C/50F
winter = again, 7 days below freezing
growing season = when the 24h mean temp has been above 5C/41F for 10 days.

The three-month-seasons are referred as 'calendar seasons'.

The seasons can't be reversed, so if the temps fall below freezing in spring for example, it's still spring and not temporarily winter again.

This method is no way very satisfactory, as it makes summers unrealistically long, and springs very short. On average that time is from mid May to late days of September. Raising the temperature threshold to 12.83C or 15C pushes the summer forward, which is not good as well. June is very much summer, and September autumn, at least mentally. Chilly Junes, like last year, can mean that the whole month is a 'spring' month, if using 15C. Examples:

2012
>10C summer: May 19 - Oct 5
>12.83C summer: May 21 - Sep 20
>15C summer: Jul 1 - Sep 6

2011
>10C summer: May 20 - Oct 8
>12.83C summer: May 31 - Sep 27
>15C summer: June 7 - Aug 28

Sounds logical as a theory, but as the seasons can't be reversed, a single 7 day warm spell in May will shift the season, even if it would be some 12C/3C for the next 7 days. Knowing how variable Mays can be in Scandinavia, I can't consider those very summerlike. Like in 2010: a high of 5.5C/42F on May 8, 27.7C/82F on May 15, 10.6C/51F on May 29.
As Patricius said earlier (last year), if it stays warm after the warm spell it should be considered summer, but if turns colder again, it's still spring.

I wanted to see how this would work for NYC (LaGuardia Airport).

Springs:
2/07/09 to 4/20/09 (73 days)
2/26/10 to 3/15/10 (18 days)
2/23/11 to 4/22/11 (59 days)
1/05/12 to 3/16/12 (72 days)
2/22/13 to N/A

Summers:
4/21/09 to 12/03/09 (227 days)
3/16/10 to 12/01/10 (261 days)
4/23/11 to 12/07/11 (229 days)
3/17/12 to 10/31/12 (229 days)

Autumns:
12/04/09 to 2/25/10 (84 days)
12/02/10 to 2/12/11 (73 days)
12/08/11 to 1/04/12 (28 days)
11/01/12 to 1/20/13 (81 days)

Winters:
1/21/13 to 2/21/13 (32 days)

Growing Seasons:
3/25/09 to 12/25/09 (276 days)
3/04/10 to 12/22/10 (294 days)
4/02/11 to 1/01/13 (641 days)

Under this definition, NYC seldom has a winter. The historic cold snap in January 2013 had exactly 7 days with means below 0°C/32°F which barely allowed for a winter. The last growing season spanned 3 years.

[dunno what to put here]

Winter start dates in Leeds using the Finnish method, used LBA for this one so there is no UHI skewing the figures.

1981/2: 8 December
1983/4: 19 January
1984/5: 7 January
1985/6: 5 February
1986/7: 8 January
1990/1: 29 January
1995/6: 24 December
2001/2: 29 December
2008/9: 1 February
2009/10: 1 January
2010/11: 25 November
2012/13: 13 January

Many years came close, more than one year had 6 consecutive days with means below freezing.

[Derek41]

Here early spring temps would be around 22-23C maximums, with still single digit minimums (I don;t live right on the coast).
Late spring, usually 25-27C maximums, with the odd very hot day, and minimums now in the mid teens.
Spring is very volatile in an Oceanic climate though, it is not uncommon for October to be cooler than September, or November to be cooler than October etc.

[bchris02]

Oklahoma has significant seasonal lag especially in March. Early spring temperatures here are probably highs in the 30s and lows in the 10s, with the occasional single digits. Late spring temperatures are highs in the upper 80s and lows in the 60s.

[cloudcrash619]

March usually has highs in the the 60's/70's, sometimes we'll have a late season snow event (even significant ones) and there's a freeze in about 95% of every March. By May, highs are in the 80's and usually by the end of the month there's already been a 90 degree reading.

[Htown2013]

When I lived up North, I always considered early Spring when flowers came up, the trees blossomed, and the grass turned green, typically by mid-April. Late Spring was when everything became fully green, typically by mid-May. In Houston, March feels like very late Spring, even early Summer at times.

[Mac15]

Originally Posted by bchris02

Oklahoma has significant seasonal lag especially in March. Early spring temperatures here are probably highs in the 30s and lows in the 10s, with the occasional single digits. Late spring temperatures are highs in the upper 80s and lows in the 60s.

In oklahoma?

[Richard82]

Around 7C would be normal here in early March rising to 15C by the end of May.

Not that there is any signs of normal temps at the moment. The last time it reached the average was 2 weeks ago, on the 3rd and since the 6th only one day has reached 6C - a max of 6.3C on the 14th.

[sulkiercupid]

For where I live the most noticeable change that marks early spring is the drop in rainfall and increased sunshine, temperatures remain similar to the winter months though with overnight lows around 10C and highs around 20C. Cold nights <5C become much less common.

By late spring it just feels like a slightly milder version of summer with dry, sunny weather prevailing and a with lows of 12C+ and highs around 27C. By this time very hot days of 35C/95F+ are possible.

[MrMarbles]

Originally Posted by bchris02

Oklahoma has significant seasonal lag especially in March. Early spring temperatures here are probably highs in the 30s and lows in the 10s, with the occasional single digits. Late spring temperatures are highs in the upper 80s and lows in the 60s.

Which Oklahoma are you talking about? The average high/low for Oklahoma City in March is 63/41F. Highs in the 30s would be significantly below average even in January.