Hopewell Rocks Provincial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hopewell Rocks Provincial Park clear sky chart from 2005-11-06 to 2024-02-20.

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% 9% 3 6% 6% 3 5% 5% 5% 7% 33%	78231
	Night	19% 10% 4 6% 6% 3 4 4 5% 6% 33%	80951
Transparency	Day	50% 7% 13% 19% 10% 1	77928
	Night	51% 6% 12% 20% 10% 1	80789
Seeing	Day	24% 19% 32% 18% 6% 1	15834
	Night	24% 17% 31% 21% 6%	23590

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	15% 11% 4 6% 6% 4 5% 4 5% 5% 35%	2207
	11th to 20th	Day	14% 13% 4 8% 6% 3 4 4 4 5% 36%	2477
	21st to end	Day	13% 8% 3 8% 7% 3 6% 6% 6% 8% 32%	3124
February	1st to 10th	Day	16% 11% 4 9% 6% 3 4 4 5% 7% 30%	1710
	11th to 20th	Day	14% 12% 4 7% 6% 3 6% 5% 5% 7% 29%	1654
	21st to end	Day	10% 11% 5% 7% 7% 3 5% 4 6% 7% 35%	1340
March	1st to 10th	Day	15% 13% 6% 8% 6% 4 5% 4 4 5% 29%	1965
	11th to 20th	Day	15% 8% 4 8% 7% 4 5% 6% 5% 6% 33%	1980
	21st to end	Day	16% 12% 5% 7% 5% 3 5% 4 5% 6% 32%	2178
April	1st to 10th	Day	19% 11% 4 7% 6% 4 5% 5% 5% 6% 27%	2134
	11th to 20th	Day	18% 10% 3 6% 6% 4 4 5% 5% 6% 33%	2250
	21st to end	Day	23% 9% 3 7% 5% 3 4 4 5% 7% 29%	2340
May	1st to 10th	Day	21% 11% 4 8% 6% 4 5% 4 5% 6% 27%	2394
	11th to 20th	Day	22% 9% 3 5% 5% 3 4 4 5% 6% 35%	2478
	21st to end	Day	17% 8% 3 8% 6% 3 4 4 5% 7% 33%	2724
June	1st to 10th	Day	24% 8% 3 6% 6% 4 5% 5% 6% 8% 26%	2619
	11th to 20th	Day	20% 6% 4 5% 6% 3 5% 5% 5% 8% 32%	2700
	21st to end	Day	25% 7% 3 6% 6% 3 4 4 5% 7% 30%	2700
July	1st to 10th	Day	15% 6% 3 6% 5% 4 5% 5% 6% 8% 36%	2700
	11th to 20th	Day	12% 6% 3 5% 6% 4 5% 6% 7% 10% 35%	2624
	21st to end	Day	16% 7% 3 6% 6% 4 6% 6% 6% 9% 31%	2674
August	1st to 10th	Day	14% 6% 3 4 5% 4 5% 6% 8% 9% 36%	2327
	11th to 20th	Day	15% 6% 3 5% 6% 4 5% 6% 7% 9% 35%	2304
	21st to end	Day	12% 6% 2 4 5% 4 5% 5% 6% 8% 42%	2513
September	1st to 10th	Day	14% 4 1 4 5% 3 5% 6% 7% 8% 42%	2160
	11th to 20th	Day	16% 7% 3 6% 5% 3 4 4 5% 6% 42%	2062
	21st to end	Day	17% 5% 2 5% 4 2 4 4 5% 5% 46%	1942
October	1st to 10th	Day	17% 7% 2 6% 4 3 4 4 5% 8% 41%	1800
	11th to 20th	Day	19% 8% 3 5% 5% 3 4 5% 5% 7% 37%	1800
	21st to end	Day	19% 8% 2 6% 7% 4 4 4 5% 7% 34%	1962
November	1st to 10th	Day	21% 10% 3 6% 5% 3 4 4 3 7% 34%	1506
	11th to 20th	Day	19% 10% 3 5% 4 3 4 5% 6% 6% 35%	1520
	21st to end	Day	18% 11% 3 6% 5% 4 4 5% 5% 5% 33%	1520
December	1st to 10th	Day	24% 11% 3 7% 4 3 4 4 4 6% 30%	1520
	11th to 20th	Day	20% 15% 4 7% 5% 4 4 4 4 5% 28%	1892
	21st to end	Day	18% 11% 5% 8% 6% 3 4 4 6% 6% 28%	2431
January	1st to 10th	Night	13% 12% 4 5% 5% 3 5% 4 4 6% 39%	4748
	11th to 20th	Night	17% 12% 4 7% 7% 4 4 4 5% 6% 31%	4483
	21st to end	Night	16% 10% 5% 7% 9% 3 4 3 4 7% 32%	4532
February	1st to 10th	Night	18% 11% 4 7% 6% 3 5% 5% 6% 6% 29%	2470
	11th to 20th	Night	15% 13% 4 8% 6% 3 5% 4 5% 7% 29%	2397
	21st to end	Night	12% 12% 6% 9% 5% 3 5% 4 5% 6% 33%	1911
March	1st to 10th	Night	15% 14% 4 7% 6% 4 5% 4 4 5% 32%	1981
	11th to 20th	Night	18% 8% 5% 7% 6% 4 5% 5% 7% 6% 29%	1979
	21st to end	Night	17% 12% 4 6% 6% 3 4 4 4 5% 34%	2178
April	1st to 10th	Night	22% 13% 4 7% 7% 3 5% 4 4 5% 27%	1824
	11th to 20th	Night	21% 11% 4 6% 6% 3 3 3 4 6% 34%	1657
	21st to end	Night	23% 10% 3 7% 5% 3 4 5% 5% 6% 30%	1620
May	1st to 10th	Night	23% 8% 4 6% 5% 3 5% 5% 5% 5% 30%	1564
	11th to 20th	Night	26% 8% 2 4 4 3 3 4 5% 7% 34%	1416
	21st to end	Night	14% 7% 3 6% 7% 3 6% 7% 7% 7% 33%	1550
June	1st to 10th	Night	25% 8% 4 6% 6% 3 4 5% 5% 7% 27%	1354
	11th to 20th	Night	20% 6% 4 7% 6% 3 5% 4 5% 7% 34%	1260
	21st to end	Night	25% 8% 3 6% 5% 5% 4 6% 5% 8% 27%	1260
July	1st to 10th	Night	16% 7% 2 5% 7% 3 5% 6% 8% 10% 33%	1260
	11th to 20th	Night	14% 7% 3 6% 6% 4 6% 6% 7% 9% 31%	1314
	21st to end	Night	15% 8% 4 6% 7% 4 7% 6% 7% 9% 28%	1640
August	1st to 10th	Night	14% 4 1 6% 6% 4 6% 6% 7% 8% 38%	1612
	11th to 20th	Night	16% 6% 3 7% 5% 3 7% 6% 7% 9% 32%	1596
	21st to end	Night	13% 6% 2 5% 5% 3 5% 5% 6% 9% 41%	1841
September	1st to 10th	Night	13% 6% 2 5% 6% 3 5% 5% 5% 8% 42%	1800
	11th to 20th	Night	16% 7% 2 5% 5% 3 3 4 4 7% 44%	1894
	21st to end	Night	16% 6% 3 5% 5% 2 4 4 5% 6% 44%	2017
October	1st to 10th	Night	19% 6% 3 5% 4 2 3 4 6% 7% 40%	2160
	11th to 20th	Night	19% 7% 3 5% 4 3 4 5% 5% 6% 39%	2160
	21st to end	Night	25% 9% 3 5% 5% 3 4 4 4 5% 34%	2390
November	1st to 10th	Night	22% 7% 3 6% 5% 3 4 3 5% 6% 35%	2570
	11th to 20th	Night	20% 8% 4 7% 5% 3 4 4 5% 6% 33%	2660
	21st to end	Night	21% 10% 4 6% 5% 3 4 4 5% 6% 34%	2660
December	1st to 10th	Night	24% 11% 3 7% 5% 3 4 4 4 6% 28%	2660
	11th to 20th	Night	26% 14% 4 5% 4 2 3 3 4 4 30%	3297
	21st to end	Night	24% 11% 5% 7% 5% 3 5% 4 3 4 30%	5236

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	51% 7% 13% 17% 10% 1	2208
	11th to 20th	Day	51% 5% 10% 19% 13% 1	2477
	21st to end	Day	48% 8% 16% 14% 14% 1	3124
February	1st to 10th	Day	54% 5% 12% 16% 12% 2	1710
	11th to 20th	Day	56% 6% 12% 15% 10% 1	1662
	21st to end	Day	47% 6% 13% 20% 11% 3	1340
March	1st to 10th	Day	58% 5% 9% 18% 9% 1	1969
	11th to 20th	Day	53% 6% 12% 17% 10% 2	1980
	21st to end	Day	56% 4 11% 16% 10% 3	2178
April	1st to 10th	Day	58% 6% 9% 15% 9% 3	2134
	11th to 20th	Day	51% 6% 10% 21% 11% 1	2250
	21st to end	Day	55% 5% 12% 16% 9% 2	2340
May	1st to 10th	Day	59% 5% 10% 15% 10% 1	2394
	11th to 20th	Day	50% 7% 9% 23% 10%	2482
	21st to end	Day	51% 7% 12% 22% 7% 1	2724
June	1st to 10th	Day	56% 8% 11% 19% 6%	2619
	11th to 20th	Day	51% 8% 12% 19% 9% 1	2700
	21st to end	Day	55% 7% 12% 16% 8% 1	2700
July	1st to 10th	Day	43% 8% 17% 22% 9%	2625
	11th to 20th	Day	42% 10% 17% 22% 8% 1	2543
	21st to end	Day	49% 10% 16% 19% 6%	2524
August	1st to 10th	Day	43% 9% 16% 26% 7%	2314
	11th to 20th	Day	45% 10% 17% 22% 6%	2304
	21st to end	Day	40% 7% 17% 25% 11%	2513
September	1st to 10th	Day	37% 9% 17% 24% 13%	2160
	11th to 20th	Day	43% 6% 11% 25% 14% 1	2062
	21st to end	Day	41% 5% 12% 28% 14% 1	1942
October	1st to 10th	Day	42% 6% 12% 28% 11% 1	1800
	11th to 20th	Day	47% 7% 14% 24% 8% 1	1800
	21st to end	Day	52% 6% 12% 20% 11%	1962
November	1st to 10th	Day	53% 5% 11% 19% 10%	1506
	11th to 20th	Day	50% 6% 14% 17% 12% 1	1520
	21st to end	Day	53% 7% 13% 18% 9%	1520
December	1st to 10th	Day	56% 6% 12% 18% 7% 1	1520
	11th to 20th	Day	60% 5% 9% 17% 8% 1	1891
	21st to end	Day	56% 7% 15% 14% 7% 1	2431
January	1st to 10th	Night	46% 5% 13% 28% 7% 1	4748
	11th to 20th	Night	52% 7% 12% 19% 9% 1	4483
	21st to end	Night	52% 6% 11% 21% 9% 1	4532
February	1st to 10th	Night	55% 6% 11% 14% 12% 2	2470
	11th to 20th	Night	55% 4 13% 15% 12% 1	2400
	21st to end	Night	52% 5% 9% 18% 14% 2	1911
March	1st to 10th	Night	56% 5% 10% 16% 12% 2	1990
	11th to 20th	Night	53% 6% 11% 16% 11% 2	1980
	21st to end	Night	53% 6% 9% 19% 11% 2	2178
April	1st to 10th	Night	61% 6% 8% 12% 10% 4	1824
	11th to 20th	Night	52% 4 11% 20% 12% 1	1657
	21st to end	Night	56% 5% 11% 14% 12% 1	1620
May	1st to 10th	Night	55% 5% 10% 17% 11% 1	1564
	11th to 20th	Night	51% 5% 10% 23% 10% 1	1417
	21st to end	Night	47% 9% 15% 19% 9% 1	1551
June	1st to 10th	Night	55% 8% 10% 18% 8%	1354
	11th to 20th	Night	49% 7% 10% 23% 9% 1	1260
	21st to end	Night	55% 10% 12% 13% 9% 1	1260
July	1st to 10th	Night	43% 10% 16% 23% 8%	1225
	11th to 20th	Night	44% 10% 14% 23% 9%	1272
	21st to end	Night	49% 11% 15% 17% 8%	1550
August	1st to 10th	Night	40% 10% 18% 23% 9%	1600
	11th to 20th	Night	46% 9% 17% 22% 6%	1596
	21st to end	Night	37% 8% 18% 27% 9%	1841
September	1st to 10th	Night	38% 8% 14% 29% 11% 1	1800
	11th to 20th	Night	40% 6% 13% 27% 14% 1	1894
	21st to end	Night	40% 6% 12% 26% 14% 1	2017
October	1st to 10th	Night	43% 5% 12% 27% 12%	2160
	11th to 20th	Night	45% 6% 14% 27% 7%	2160
	21st to end	Night	54% 6% 11% 18% 11% 1	2390
November	1st to 10th	Night	50% 7% 13% 19% 10% 1	2570
	11th to 20th	Night	52% 6% 13% 18% 10% 1	2660
	21st to end	Night	52% 6% 13% 19% 9% 1	2660
December	1st to 10th	Night	56% 6% 11% 19% 7% 1	2660
	11th to 20th	Night	59% 4 8% 17% 10% 1	3299
	21st to end	Night	59% 5% 13% 16% 7% 1	5236

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	31% 23% 30% 16% 1	180
	11th to 20th	Day	32% 23% 30% 11% 4	298
	21st to end	Day	18% 22% 39% 16% 5%	407
February	1st to 10th	Day	24% 26% 30% 15% 4 1	370
	11th to 20th	Day	25% 28% 31% 12% 3 1	363
	21st to end	Day	19% 23% 37% 17% 4	284
March	1st to 10th	Day	25% 26% 37% 10% 2 1	420
	11th to 20th	Day	21% 26% 33% 15% 4 1	420
	21st to end	Day	28% 24% 32% 11% 4 1	462
April	1st to 10th	Day	33% 27% 26% 11% 2 1	420
	11th to 20th	Day	29% 26% 28% 13% 4	412
	21st to end	Day	28% 24% 29% 13% 6% 1	420
May	1st to 10th	Day	32% 22% 26% 16% 4 1	477
	11th to 20th	Day	28% 20% 27% 18% 6% 1	624
	21st to end	Day	25% 20% 33% 19% 3	680
June	1st to 10th	Day	31% 15% 31% 16% 6%	630
	11th to 20th	Day	23% 17% 33% 19% 7% 1	630
	21st to end	Day	24% 15% 28% 25% 7% 1	630
July	1st to 10th	Day	21% 14% 38% 20% 6% 1	620
	11th to 20th	Day	16% 8% 39% 26% 10% 1	618
	21st to end	Day	19% 10% 39% 25% 7%	614
August	1st to 10th	Day	15% 9% 37% 31% 7% 1	446
	11th to 20th	Day	19% 10% 33% 26% 9% 1	439
	21st to end	Day	15% 17% 32% 25% 9% 2	495
September	1st to 10th	Day	13% 13% 42% 22% 8% 2	450
	11th to 20th	Day	24% 14% 31% 20% 9% 2	450
	21st to end	Day	21% 17% 34% 19% 8% 2	430
October	1st to 10th	Day	23% 14% 29% 20% 11% 2	360
	11th to 20th	Day	23% 19% 29% 21% 7% 1	360
	21st to end	Day	27% 20% 32% 14% 6% 1	396
November	1st to 10th	Day	27% 22% 30% 12% 8% 1	365
	11th to 20th	Day	29% 22% 28% 14% 5% 1	370
	21st to end	Day	30% 23% 32% 11% 4	370
December	1st to 10th	Day	31% 22% 30% 14% 3	370
	11th to 20th	Day	31% 30% 27% 11% 1	356
	21st to end	Day	26% 28% 33% 10% 3	198
January	1st to 10th	Night	26% 22% 31% 18% 4	850
	11th to 20th	Night	27% 21% 30% 17% 4	826
	21st to end	Night	19% 24% 34% 18% 4	836
February	1st to 10th	Night	27% 22% 31% 17% 3	760
	11th to 20th	Night	26% 24% 33% 15% 2 1	742
	21st to end	Night	22% 19% 36% 19% 3 1	592
March	1st to 10th	Night	24% 21% 35% 19% 2	720
	11th to 20th	Night	23% 18% 32% 19% 7%	720
	21st to end	Night	25% 17% 32% 20% 5%	792
April	1st to 10th	Night	31% 18% 31% 17% 3	564
	11th to 20th	Night	28% 16% 30% 20% 5%	534
	21st to end	Night	29% 17% 28% 19% 6% 1	540
May	1st to 10th	Night	29% 13% 30% 22% 6%	540
	11th to 20th	Night	28% 14% 28% 22% 7%	532
	21st to end	Night	21% 14% 41% 20% 4	583
June	1st to 10th	Night	29% 11% 31% 24% 6%	454
	11th to 20th	Night	22% 9% 33% 30% 6% 1	360
	21st to end	Night	24% 9% 29% 32% 6%	360
July	1st to 10th	Night	19% 7% 41% 24% 9%	350
	11th to 20th	Night	16% 10% 35% 31% 8% 1	402
	21st to end	Night	19% 7% 36% 32% 7%	590
August	1st to 10th	Night	15% 5% 36% 33% 11%	538
	11th to 20th	Night	18% 7% 30% 32% 12% 1	532
	21st to end	Night	14% 10% 30% 33% 12% 1	594
September	1st to 10th	Night	18% 11% 36% 28% 8%	540
	11th to 20th	Night	19% 11% 27% 31% 11% 1	634
	21st to end	Night	20% 13% 31% 27% 9%	720
October	1st to 10th	Night	23% 12% 28% 27% 10% 1	720
	11th to 20th	Night	23% 15% 33% 21% 8% 1	720
	21st to end	Night	32% 20% 28% 18% 3	792
November	1st to 10th	Night	28% 19% 28% 18% 6% 1	818
	11th to 20th	Night	25% 22% 29% 18% 5% 1	850
	21st to end	Night	26% 23% 30% 18% 3	850
December	1st to 10th	Night	30% 21% 30% 16% 3	850
	11th to 20th	Night	29% 25% 30% 13% 2	850
	21st to end	Night	30% 24% 26% 17% 3 1	935

Page generated at 2024-02-17 07:28:41. Version ac07

Copyright 2024 Attilla Danko