Summerside
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Summerside clear sky chart from 2005-11-06 to 2024-01-22.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	17% 10% 4 7% 6% 3 5% 4 5% 7% 31%	74929
	Night	19% 11% 4 8% 6% 3 5% 4 5% 6% 29%	74995
Transparency	Day	37% 35% 8% 14% 5%	74622
	Night	39% 35% 8% 13% 5%	74837
Seeing	Day	23% 11% 28% 25% 11% 2	15922
	Night	25% 12% 30% 25% 8% 1	23504

By Month

Percentage Cloud Cover NE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	17% 16% 6% 10% 8% 4 5% 3 4 5% 21%	1327
	11th to 20th	Day	18% 15% 6% 9% 9% 4 5% 4 5% 4 20%	1487
	21st to end	Day	12% 10% 5% 9% 8% 4 5% 5% 5% 6% 33%	1773
February	1st to 10th	Day	16% 12% 5% 8% 5% 3 5% 4 4 6% 32%	1620
	11th to 20th	Day	16% 15% 4 7% 7% 5% 5% 5% 4 6% 28%	1573
	21st to end	Day	11% 11% 5% 8% 5% 3 5% 5% 6% 7% 34%	1345
March	1st to 10th	Day	15% 12% 6% 7% 6% 3 5% 5% 5% 6% 30%	1940
	11th to 20th	Day	13% 10% 5% 10% 9% 3 5% 4 5% 5% 30%	1980
	21st to end	Day	18% 14% 6% 8% 6% 3 3 4 3 6% 30%	2186
April	1st to 10th	Day	19% 11% 4 7% 6% 3 5% 4 5% 6% 31%	2160
	11th to 20th	Day	18% 11% 3 5% 5% 3 4 4 5% 8% 34%	2220
	21st to end	Day	22% 11% 3 6% 5% 2 5% 5% 6% 7% 28%	2340
May	1st to 10th	Day	24% 10% 3 7% 5% 3 5% 4 4 7% 28%	2453
	11th to 20th	Day	20% 9% 3 6% 6% 3 3 4 4 6% 36%	2478
	21st to end	Day	18% 9% 3 6% 5% 3 5% 4 5% 7% 35%	2724
June	1st to 10th	Day	25% 9% 3 6% 6% 3 5% 4 6% 7% 27%	2597
	11th to 20th	Day	19% 8% 3 6% 5% 3 4 4 5% 7% 35%	2700
	21st to end	Day	24% 8% 3 6% 5% 3 5% 5% 5% 6% 32%	2700
July	1st to 10th	Day	15% 6% 2 5% 5% 3 5% 5% 7% 9% 39%	2700
	11th to 20th	Day	13% 5% 2 5% 5% 4 5% 6% 8% 9% 37%	2601
	21st to end	Day	15% 7% 3 8% 6% 3 5% 5% 7% 9% 33%	2745
August	1st to 10th	Day	12% 8% 3 5% 5% 3 4 6% 6% 7% 41%	2333
	11th to 20th	Day	15% 5% 3 6% 6% 4 4 6% 6% 8% 36%	2304
	21st to end	Day	13% 6% 2 5% 5% 3 4 4 6% 8% 44%	2491
September	1st to 10th	Day	16% 5% 2 4 4 3 4 5% 6% 9% 42%	2160
	11th to 20th	Day	19% 8% 3 5% 5% 3 3 4 5% 6% 40%	2111
	21st to end	Day	18% 6% 2 6% 5% 3 4 3 4 6% 43%	1912
October	1st to 10th	Day	17% 8% 3 6% 5% 3 4 5% 5% 7% 37%	1800
	11th to 20th	Day	19% 11% 4 7% 6% 4 5% 4 6% 7% 27%	1800
	21st to end	Day	20% 12% 4 8% 8% 3 5% 5% 5% 7% 25%	1949
November	1st to 10th	Day	19% 11% 4 7% 8% 4 6% 4 4 6% 26%	1491
	11th to 20th	Day	18% 15% 6% 9% 7% 3 6% 4 5% 7% 19%	1520
	21st to end	Day	18% 14% 6% 11% 9% 4 5% 4 4 7% 18%	1520
December	1st to 10th	Day	24% 13% 6% 12% 8% 3 5% 4 4 5% 16%	1520
	11th to 20th	Day	17% 18% 8% 12% 9% 4 6% 4 3 3 16%	1906
	21st to end	Day	17% 13% 9% 14% 9% 4 5% 3 3 5% 18%	2463
January	1st to 10th	Night	18% 13% 6% 10% 8% 3 6% 4 4 4 23%	2838
	11th to 20th	Night	17% 13% 5% 9% 8% 3 6% 5% 5% 6% 24%	2688
	21st to end	Night	13% 11% 4 8% 6% 4 5% 5% 5% 6% 32%	2617
February	1st to 10th	Night	16% 12% 5% 8% 5% 4 5% 4 5% 6% 29%	2340
	11th to 20th	Night	17% 15% 5% 9% 7% 4 5% 4 5% 6% 25%	2273
	21st to end	Night	13% 11% 5% 8% 7% 4 5% 4 5% 5% 32%	1910
March	1st to 10th	Night	18% 13% 4 8% 7% 3 4 4 5% 6% 29%	2007
	11th to 20th	Night	18% 11% 4 8% 8% 4 5% 4 5% 4 29%	1979
	21st to end	Night	19% 14% 4 9% 5% 2 4 3 4 4 32%	2170
April	1st to 10th	Night	22% 12% 4 8% 6% 4 4 5% 5% 5% 25%	1800
	11th to 20th	Night	21% 10% 3 6% 6% 3 4 4 4 7% 32%	1688
	21st to end	Night	22% 13% 4 7% 7% 2 3 4 4 6% 28%	1620
May	1st to 10th	Night	25% 8% 3 5% 5% 3 4 4 4 6% 31%	1505
	11th to 20th	Night	22% 8% 3 6% 6% 3 3 4 5% 6% 36%	1416
	21st to end	Night	15% 9% 4 6% 5% 3 4 5% 6% 9% 35%	1550
June	1st to 10th	Night	25% 9% 4 6% 6% 3 5% 4 5% 7% 28%	1377
	11th to 20th	Night	20% 7% 2 5% 6% 2 5% 4 5% 7% 37%	1260
	21st to end	Night	22% 9% 4 7% 5% 3 5% 4 5% 6% 30%	1260
July	1st to 10th	Night	17% 6% 2 5% 6% 3 7% 5% 6% 8% 35%	1260
	11th to 20th	Night	14% 7% 3 6% 6% 4 7% 7% 7% 8% 33%	1340
	21st to end	Night	14% 8% 4 7% 6% 4 6% 6% 5% 7% 32%	1573
August	1st to 10th	Night	14% 6% 3 6% 6% 4 5% 6% 6% 7% 38%	1602
	11th to 20th	Night	15% 7% 3 7% 6% 4 6% 5% 5% 8% 34%	1596
	21st to end	Night	14% 5% 3 6% 6% 3 4 5% 6% 9% 40%	1864
September	1st to 10th	Night	16% 6% 3 4 4 3 4 4 6% 8% 42%	1800
	11th to 20th	Night	17% 7% 3 5% 5% 2 4 4 4 6% 42%	1846
	21st to end	Night	17% 6% 2 5% 5% 3 3 5% 5% 6% 43%	2047
October	1st to 10th	Night	20% 6% 3 5% 5% 3 3 4 5% 7% 38%	2160
	11th to 20th	Night	20% 8% 3 7% 5% 3 5% 4 5% 8% 33%	2160
	21st to end	Night	24% 11% 4 7% 6% 3 4 4 5% 5% 27%	2407
November	1st to 10th	Night	21% 11% 5% 7% 5% 3 5% 4 4 6% 28%	2583
	11th to 20th	Night	20% 12% 5% 8% 7% 4 5% 5% 5% 6% 24%	2660
	21st to end	Night	23% 14% 5% 9% 6% 3 5% 4 5% 7% 21%	2660
December	1st to 10th	Night	23% 14% 6% 9% 9% 4 5% 5% 4 5% 16%	2660
	11th to 20th	Night	20% 18% 7% 10% 8% 4 4 4 4 4 17%	3293
	21st to end	Night	23% 15% 6% 11% 6% 3 4 4 3 5% 21%	5186

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	48% 39% 5% 6% 3	1328
	11th to 20th	Day	45% 39% 3 9% 4	1487
	21st to end	Day	35% 36% 7% 13% 9%	1773
February	1st to 10th	Day	38% 35% 9% 9% 8%	1620
	11th to 20th	Day	41% 36% 6% 11% 5% 1	1581
	21st to end	Day	37% 35% 8% 13% 8% 1	1345
March	1st to 10th	Day	41% 35% 6% 13% 5%	1944
	11th to 20th	Day	37% 35% 7% 14% 6% 1	1980
	21st to end	Day	40% 34% 7% 12% 5% 1	2186
April	1st to 10th	Day	37% 35% 6% 14% 7% 1	2160
	11th to 20th	Day	34% 34% 6% 15% 10% 1	2220
	21st to end	Day	35% 35% 8% 13% 7% 1	2340
May	1st to 10th	Day	39% 35% 6% 11% 7% 1	2453
	11th to 20th	Day	35% 36% 5% 17% 7%	2482
	21st to end	Day	32% 36% 10% 16% 6%	2724
June	1st to 10th	Day	40% 36% 8% 13% 3	2597
	11th to 20th	Day	35% 35% 7% 16% 6% 1	2700
	21st to end	Day	39% 36% 9% 11% 4 1	2700
July	1st to 10th	Day	29% 37% 12% 18% 4	2625
	11th to 20th	Day	30% 37% 12% 15% 6%	2520
	21st to end	Day	33% 37% 11% 16% 3	2592
August	1st to 10th	Day	31% 36% 10% 19% 4	2319
	11th to 20th	Day	31% 35% 12% 19% 3	2304
	21st to end	Day	26% 36% 9% 22% 7%	2491
September	1st to 10th	Day	29% 36% 11% 17% 7%	2160
	11th to 20th	Day	31% 36% 7% 17% 9% 1	2111
	21st to end	Day	30% 35% 7% 20% 7%	1912
October	1st to 10th	Day	33% 35% 9% 17% 6% 1	1800
	11th to 20th	Day	39% 35% 9% 14% 3	1800
	21st to end	Day	41% 36% 7% 11% 4	1949
November	1st to 10th	Day	37% 39% 7% 12% 4	1491
	11th to 20th	Day	39% 39% 9% 10% 4	1520
	21st to end	Day	43% 41% 8% 7% 2	1520
December	1st to 10th	Day	45% 40% 7% 7% 2	1520
	11th to 20th	Day	55% 31% 4 7% 3	1905
	21st to end	Day	56% 24% 10% 8% 2	2463
January	1st to 10th	Night	43% 38% 7% 9% 2	2838
	11th to 20th	Night	41% 39% 7% 9% 4	2688
	21st to end	Night	35% 36% 7% 14% 7% 1	2617
February	1st to 10th	Night	38% 35% 8% 11% 8% 1	2340
	11th to 20th	Night	42% 36% 6% 9% 6% 1	2276
	21st to end	Night	38% 35% 7% 14% 6% 1	1910
March	1st to 10th	Night	42% 34% 6% 12% 5% 1	2016
	11th to 20th	Night	39% 35% 5% 15% 5% 1	1980
	21st to end	Night	39% 35% 5% 13% 7% 1	2170
April	1st to 10th	Night	41% 35% 7% 9% 8% 1	1800
	11th to 20th	Night	36% 33% 5% 15% 10%	1688
	21st to end	Night	39% 34% 5% 11% 10% 1	1620
May	1st to 10th	Night	36% 36% 6% 14% 7% 2	1505
	11th to 20th	Night	35% 35% 5% 17% 7% 1	1417
	21st to end	Night	30% 37% 10% 17% 6%	1551
June	1st to 10th	Night	42% 35% 8% 11% 4	1377
	11th to 20th	Night	33% 36% 7% 15% 8%	1260
	21st to end	Night	40% 36% 12% 8% 5%	1260
July	1st to 10th	Night	30% 37% 11% 18% 4	1225
	11th to 20th	Night	34% 38% 10% 12% 5%	1298
	21st to end	Night	35% 37% 10% 13% 5%	1486
August	1st to 10th	Night	32% 35% 9% 19% 5%	1591
	11th to 20th	Night	33% 34% 14% 16% 2	1596
	21st to end	Night	29% 35% 12% 17% 6%	1864
September	1st to 10th	Night	29% 35% 7% 22% 7%	1800
	11th to 20th	Night	30% 35% 7% 19% 9% 1	1846
	21st to end	Night	29% 35% 7% 19% 8% 1	2047
October	1st to 10th	Night	31% 35% 8% 19% 7%	2160
	11th to 20th	Night	35% 35% 9% 18% 4	2160
	21st to end	Night	41% 36% 5% 11% 6%	2407
November	1st to 10th	Night	36% 39% 7% 12% 5%	2583
	11th to 20th	Night	39% 39% 7% 10% 5%	2660
	21st to end	Night	40% 39% 9% 9% 3	2660
December	1st to 10th	Night	45% 38% 7% 8% 3	2660
	11th to 20th	Night	53% 31% 5% 9% 2	3295
	21st to end	Night	55% 23% 10% 9% 2	5186

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	26% 21% 29% 19% 4 1	180
	11th to 20th	Day	28% 15% 32% 18% 6%	337
	21st to end	Day	17% 13% 37% 28% 4 1	378
February	1st to 10th	Day	26% 14% 36% 20% 3 1	340
	11th to 20th	Day	26% 15% 32% 22% 4	336
	21st to end	Day	16% 16% 33% 26% 8% 1	280
March	1st to 10th	Day	23% 13% 33% 25% 6% 1	404
	11th to 20th	Day	18% 15% 33% 26% 7% 1	420
	21st to end	Day	27% 12% 29% 23% 8% 1	462
April	1st to 10th	Day	26% 16% 33% 18% 6%	420
	11th to 20th	Day	23% 14% 32% 20% 10% 2	412
	21st to end	Day	25% 13% 27% 22% 12% 1	420
May	1st to 10th	Day	32% 10% 26% 22% 7% 3	536
	11th to 20th	Day	25% 9% 27% 23% 14% 3	624
	21st to end	Day	24% 9% 32% 26% 9% 1	680
June	1st to 10th	Day	31% 6% 24% 26% 11% 2	630
	11th to 20th	Day	22% 7% 27% 29% 13% 2	630
	21st to end	Day	26% 5% 20% 33% 14% 3	630
July	1st to 10th	Day	19% 5% 29% 28% 16% 3	620
	11th to 20th	Day	15% 5% 25% 33% 18% 3	618
	21st to end	Day	20% 6% 21% 35% 16% 2	685
August	1st to 10th	Day	13% 5% 23% 35% 19% 5%	452
	11th to 20th	Day	17% 5% 22% 30% 21% 5%	439
	21st to end	Day	14% 8% 24% 30% 19% 5%	495
September	1st to 10th	Day	16% 5% 30% 32% 14% 4	450
	11th to 20th	Day	24% 11% 25% 24% 14% 2	450
	21st to end	Day	21% 9% 31% 24% 11% 4	416
October	1st to 10th	Day	21% 12% 26% 23% 16% 3	360
	11th to 20th	Day	23% 16% 26% 23% 10% 2	360
	21st to end	Day	26% 14% 31% 20% 8% 1	396
November	1st to 10th	Day	23% 18% 34% 18% 6% 1	365
	11th to 20th	Day	28% 18% 30% 17% 6% 1	370
	21st to end	Day	30% 18% 31% 18% 3	370
December	1st to 10th	Day	32% 18% 29% 18% 3	370
	11th to 20th	Day	29% 22% 34% 12% 2	370
	21st to end	Day	20% 21% 36% 19% 3 1	217
January	1st to 10th	Night	25% 16% 33% 21% 5%	850
	11th to 20th	Night	25% 15% 32% 22% 5%	850
	21st to end	Night	19% 15% 34% 23% 8% 1	809
February	1st to 10th	Night	24% 15% 34% 22% 5% 1	720
	11th to 20th	Night	25% 15% 35% 21% 4	703
	21st to end	Night	20% 10% 34% 26% 8% 1	592
March	1st to 10th	Night	24% 10% 35% 27% 4	720
	11th to 20th	Night	23% 13% 29% 26% 8% 1	720
	21st to end	Night	27% 11% 28% 24% 9% 1	784
April	1st to 10th	Night	27% 14% 31% 23% 6%	540
	11th to 20th	Night	27% 9% 29% 25% 9%	534
	21st to end	Night	28% 9% 30% 24% 9% 1	540
May	1st to 10th	Night	29% 6% 27% 25% 10% 2	540
	11th to 20th	Night	25% 7% 27% 29% 10% 2	532
	21st to end	Night	20% 9% 38% 27% 5%	583
June	1st to 10th	Night	29% 5% 29% 30% 6% 1	477
	11th to 20th	Night	21% 6% 26% 37% 9% 1	360
	21st to end	Night	26% 5% 26% 32% 10% 1	360
July	1st to 10th	Night	20% 5% 31% 30% 14%	350
	11th to 20th	Night	14% 6% 30% 40% 10%	428
	21st to end	Night	17% 5% 28% 38% 12% 1	590
August	1st to 10th	Night	16% 3 29% 35% 16% 1	538
	11th to 20th	Night	16% 5% 26% 36% 16% 1	532
	21st to end	Night	17% 5% 24% 34% 19% 2	594
September	1st to 10th	Night	18% 7% 33% 31% 10% 1	540
	11th to 20th	Night	21% 9% 20% 37% 12% 1	586
	21st to end	Night	21% 10% 30% 29% 9% 1	720
October	1st to 10th	Night	23% 8% 28% 30% 11% 1	720
	11th to 20th	Night	24% 11% 31% 25% 8% 1	720
	21st to end	Night	32% 15% 28% 19% 6%	807
November	1st to 10th	Night	32% 15% 28% 20% 4 1	830
	11th to 20th	Night	29% 19% 26% 19% 5% 1	850
	21st to end	Night	32% 18% 26% 20% 3	850
December	1st to 10th	Night	31% 17% 30% 19% 3	850
	11th to 20th	Night	26% 24% 33% 14% 3	850
	21st to end	Night	30% 18% 29% 19% 3 1	935

Page generated at 2024-01-19 10:28:35. Version ac07

Copyright 2024 Attilla Danko