Bonnechere Provincial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bonnechere Provincial Park clear sky chart from 2005-11-06 to 2024-01-13.

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	16% 10% 4 8% 6% 4 5% 4 5% 6% 31%	74705
	Night	16% 11% 4 8% 6% 3 4 4 5% 6% 31%	75022
Transparency	Day	53% 6% 11% 19% 10% 1	74410
	Night	54% 6% 11% 19% 10% 1	74851
Seeing	Day	23% 16% 31% 19% 9% 3	13245
	Night	22% 14% 31% 24% 9% 1	22561

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	14% 15% 7% 13% 9% 4 5% 4 5% 4 21%	1517
	11th to 20th	Day	16% 13% 6% 12% 9% 4 5% 4 4 5% 21%	1456
	21st to end	Day	11% 14% 7% 12% 9% 6% 6% 5% 4 4 24%	1731
February	1st to 10th	Day	11% 15% 7% 13% 11% 4 5% 4 5% 5% 20%	1620
	11th to 20th	Day	12% 16% 6% 11% 6% 4 5% 5% 5% 6% 24%	1573
	21st to end	Day	18% 15% 5% 7% 7% 5% 4 6% 5% 5% 23%	1404
March	1st to 10th	Day	14% 13% 6% 10% 8% 4 4 4 5% 5% 28%	1887
	11th to 20th	Day	13% 13% 6% 10% 8% 4 5% 5% 4 4 28%	1980
	21st to end	Day	17% 10% 4 6% 6% 3 3 4 4 6% 37%	2228
April	1st to 10th	Day	20% 13% 4 6% 6% 4 5% 5% 4 5% 29%	2160
	11th to 20th	Day	22% 8% 4 6% 5% 4 3 4 4 5% 36%	2138
	21st to end	Day	21% 10% 3 7% 5% 3 4 4 5% 5% 33%	2340
May	1st to 10th	Day	18% 9% 3 6% 6% 3 4 4 5% 6% 35%	2492
	11th to 20th	Day	17% 9% 3 7% 6% 4 4 4 5% 5% 36%	2478
	21st to end	Day	14% 7% 3 6% 6% 4 4 5% 5% 7% 39%	2725
June	1st to 10th	Day	20% 8% 3 6% 6% 3 5% 5% 5% 7% 31%	2520
	11th to 20th	Day	15% 5% 3 6% 5% 3 4 5% 6% 8% 39%	2520
	21st to end	Day	16% 7% 3 6% 6% 4 6% 5% 5% 8% 34%	2520
July	1st to 10th	Day	12% 6% 3 6% 5% 3 6% 5% 6% 8% 40%	2520
	11th to 20th	Day	12% 6% 3 5% 6% 4 6% 7% 7% 7% 39%	2520
	21st to end	Day	11% 6% 2 6% 6% 3 6% 7% 6% 10% 37%	2744
August	1st to 10th	Day	12% 6% 2 7% 8% 4 5% 5% 6% 8% 36%	2375
	11th to 20th	Day	12% 6% 3 6% 7% 4 6% 5% 7% 7% 38%	2303
	21st to end	Day	14% 6% 2 6% 6% 5% 6% 6% 6% 8% 35%	2430
September	1st to 10th	Day	15% 6% 3 5% 5% 3 5% 4 6% 8% 41%	2160
	11th to 20th	Day	14% 6% 3 6% 6% 2 4 5% 4 6% 44%	2160
	21st to end	Day	19% 7% 3 6% 6% 3 5% 5% 4 7% 35%	1886
October	1st to 10th	Day	20% 8% 3 6% 5% 4 5% 4 5% 6% 35%	1800
	11th to 20th	Day	23% 11% 5% 8% 7% 4 4 4 4 5% 25%	1800
	21st to end	Day	27% 12% 5% 8% 6% 4 4 4 4 5% 22%	1908
November	1st to 10th	Day	15% 12% 4 8% 6% 3 4 3 5% 7% 33%	1572
	11th to 20th	Day	16% 14% 5% 8% 8% 3 5% 3 5% 6% 25%	1520
	21st to end	Day	22% 16% 7% 10% 8% 4 5% 3 4 4 17%	1520
December	1st to 10th	Day	19% 19% 8% 11% 8% 4 4 3 3 4 16%	1520
	11th to 20th	Day	18% 17% 6% 9% 7% 3 5% 4 4 5% 21%	1906
	21st to end	Day	25% 20% 7% 12% 6% 2 3 2 2 4 18%	2772
January	1st to 10th	Night	16% 17% 7% 12% 9% 5% 5% 5% 4 5% 16%	2649
	11th to 20th	Night	15% 15% 6% 11% 9% 5% 6% 4 4 4 20%	2549
	21st to end	Night	10% 14% 6% 11% 8% 4 5% 4 5% 5% 26%	2624
February	1st to 10th	Night	11% 15% 6% 12% 10% 6% 5% 5% 4 6% 20%	2340
	11th to 20th	Night	12% 14% 7% 10% 7% 4 5% 5% 5% 5% 27%	2273
	21st to end	Night	13% 14% 6% 10% 7% 3 5% 5% 4 6% 26%	1850
March	1st to 10th	Night	14% 13% 6% 8% 8% 3 4 5% 3 5% 30%	2059
	11th to 20th	Night	13% 12% 7% 7% 6% 4 4 4 4 6% 32%	1979
	21st to end	Night	12% 11% 4 8% 6% 2 3 4 5% 6% 38%	2127
April	1st to 10th	Night	19% 13% 4 7% 6% 3 3 4 5% 5% 31%	1800
	11th to 20th	Night	19% 10% 3 6% 5% 3 4 3 4 6% 38%	1775
	21st to end	Night	19% 10% 3 8% 5% 3 4 5% 4 5% 32%	1630
May	1st to 10th	Night	19% 8% 3 5% 5% 3 5% 3 6% 7% 37%	1468
	11th to 20th	Night	18% 6% 2 5% 5% 4 4 3 5% 7% 40%	1415
	21st to end	Night	11% 5% 3 5% 6% 4 5% 5% 6% 7% 43%	1550
June	1st to 10th	Night	18% 7% 3 6% 5% 3 5% 5% 6% 7% 36%	1440
	11th to 20th	Night	14% 6% 2 4 4 3 6% 5% 4 8% 44%	1440
	21st to end	Night	15% 7% 3 5% 6% 3 5% 5% 5% 9% 36%	1440
July	1st to 10th	Night	8% 5% 2 4 5% 3 6% 6% 6% 8% 48%	1440
	11th to 20th	Night	12% 5% 3 5% 4 3 4 5% 6% 7% 45%	1440
	21st to end	Night	9% 5% 2 5% 5% 3 6% 5% 7% 10% 44%	1574
August	1st to 10th	Night	10% 5% 2 6% 6% 3 6% 5% 6% 8% 44%	1561
	11th to 20th	Night	10% 4 2 5% 5% 3 5% 5% 6% 8% 47%	1598
	21st to end	Night	13% 5% 2 6% 5% 3 4 4 6% 7% 44%	1908
September	1st to 10th	Night	12% 5% 2 5% 5% 3 4 6% 5% 7% 47%	1800
	11th to 20th	Night	15% 5% 3 5% 4 2 4 4 5% 6% 48%	1800
	21st to end	Night	17% 7% 2 5% 5% 3 4 4 5% 7% 41%	2072
October	1st to 10th	Night	22% 7% 3 6% 4 3 3 4 3 5% 40%	2160
	11th to 20th	Night	21% 10% 3 7% 6% 3 4 4 5% 6% 29%	2160
	21st to end	Night	23% 13% 4 7% 6% 3 3 4 5% 6% 26%	2447
November	1st to 10th	Night	17% 11% 3 7% 6% 3 4 4 6% 6% 32%	2502
	11th to 20th	Night	16% 13% 5% 8% 8% 3 5% 4 5% 6% 26%	2660
	21st to end	Night	21% 15% 5% 9% 8% 4 4 4 4 5% 22%	2660
December	1st to 10th	Night	19% 19% 7% 11% 7% 4 5% 4 4 5% 16%	2660
	11th to 20th	Night	18% 17% 6% 11% 6% 3 4 4 3 5% 23%	3288
	21st to end	Night	26% 19% 6% 12% 7% 3 3 3 3 4 14%	4884

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	68% 6% 8% 14% 5%	1518
	11th to 20th	Day	66% 5% 7% 11% 10% 1	1456
	21st to end	Day	64% 5% 7% 13% 9% 2	1731
February	1st to 10th	Day	66% 5% 8% 15% 5% 1	1620
	11th to 20th	Day	59% 5% 13% 13% 9% 1	1582
	21st to end	Day	62% 5% 8% 14% 10% 1	1404
March	1st to 10th	Day	59% 4 10% 16% 10% 2	1890
	11th to 20th	Day	60% 5% 9% 15% 10% 2	1980
	21st to end	Day	50% 4 8% 18% 13% 5%	2228
April	1st to 10th	Day	57% 5% 7% 17% 10% 3	2160
	11th to 20th	Day	51% 4 8% 22% 14% 2	2138
	21st to end	Day	53% 4 8% 16% 15% 3	2340
May	1st to 10th	Day	49% 5% 9% 19% 13% 5%	2492
	11th to 20th	Day	49% 5% 8% 21% 15% 2	2482
	21st to end	Day	44% 7% 11% 20% 13% 4	2725
June	1st to 10th	Day	52% 6% 10% 19% 12% 1	2520
	11th to 20th	Day	42% 8% 11% 23% 14% 2	2520
	21st to end	Day	47% 8% 12% 20% 12% 1	2520
July	1st to 10th	Day	39% 8% 11% 27% 14% 1	2450
	11th to 20th	Day	39% 9% 14% 25% 12% 1	2445
	21st to end	Day	41% 8% 14% 26% 10%	2591
August	1st to 10th	Day	44% 9% 14% 21% 11% 1	2361
	11th to 20th	Day	43% 9% 15% 24% 8% 1	2303
	21st to end	Day	43% 10% 14% 23% 10% 1	2430
September	1st to 10th	Day	40% 8% 13% 26% 12% 1	2160
	11th to 20th	Day	41% 7% 10% 31% 11%	2160
	21st to end	Day	49% 6% 12% 24% 8%	1886
October	1st to 10th	Day	51% 6% 11% 19% 12% 1	1800
	11th to 20th	Day	61% 7% 12% 15% 5% 1	1800
	21st to end	Day	64% 7% 10% 13% 5% 1	1908
November	1st to 10th	Day	52% 5% 14% 22% 7%	1572
	11th to 20th	Day	59% 6% 13% 13% 7% 1	1520
	21st to end	Day	71% 5% 10% 9% 5% 1	1520
December	1st to 10th	Day	73% 5% 8% 9% 4	1520
	11th to 20th	Day	65% 8% 9% 11% 7%	1906
	21st to end	Day	74% 3 6% 14% 3	2772
January	1st to 10th	Night	70% 7% 9% 10% 5%	2649
	11th to 20th	Night	67% 6% 8% 10% 7% 1	2549
	21st to end	Night	60% 5% 9% 16% 11%	2624
February	1st to 10th	Night	65% 6% 10% 13% 6% 1	2340
	11th to 20th	Night	59% 5% 11% 18% 7% 1	2275
	21st to end	Night	57% 6% 10% 18% 9% 1	1850
March	1st to 10th	Night	57% 5% 10% 16% 11% 2	2069
	11th to 20th	Night	54% 4 11% 18% 12% 1	1980
	21st to end	Night	47% 5% 9% 20% 16% 3	2127
April	1st to 10th	Night	55% 6% 8% 18% 11% 2	1800
	11th to 20th	Night	49% 4 8% 23% 13% 2	1775
	21st to end	Night	54% 5% 7% 16% 15% 2	1630
May	1st to 10th	Night	48% 5% 8% 19% 16% 4	1468
	11th to 20th	Night	44% 5% 9% 23% 17% 3	1416
	21st to end	Night	37% 8% 14% 21% 17% 3	1551
June	1st to 10th	Night	47% 7% 12% 22% 11% 1	1440
	11th to 20th	Night	38% 7% 12% 25% 16% 2	1440
	21st to end	Night	43% 9% 14% 20% 13% 1	1440
July	1st to 10th	Night	32% 9% 14% 25% 19% 2	1400
	11th to 20th	Night	36% 8% 13% 28% 13%	1392
	21st to end	Night	33% 10% 16% 29% 11% 1	1486
August	1st to 10th	Night	37% 9% 16% 25% 13%	1551
	11th to 20th	Night	33% 9% 19% 28% 11% 1	1598
	21st to end	Night	37% 8% 16% 28% 10% 1	1908
September	1st to 10th	Night	37% 8% 13% 29% 14% 1	1800
	11th to 20th	Night	37% 7% 15% 31% 10%	1800
	21st to end	Night	42% 7% 13% 30% 8%	2072
October	1st to 10th	Night	47% 7% 12% 22% 13%	2160
	11th to 20th	Night	55% 8% 12% 18% 7%	2160
	21st to end	Night	60% 6% 10% 15% 8%	2447
November	1st to 10th	Night	52% 6% 15% 19% 8%	2502
	11th to 20th	Night	59% 7% 12% 15% 7% 1	2660
	21st to end	Night	65% 6% 12% 13% 3	2660
December	1st to 10th	Night	71% 6% 9% 10% 3	2660
	11th to 20th	Night	64% 6% 9% 13% 7% 1	3288
	21st to end	Night	76% 4 6% 11% 3	4884

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	21% 22% 35% 19% 3 1	180
	11th to 20th	Day	25% 16% 36% 16% 5% 1	164
	21st to end	Day	24% 18% 33% 18% 6%	242
February	1st to 10th	Day	26% 29% 34% 8% 3 1	240
	11th to 20th	Day	28% 23% 41% 7% 1	240
	21st to end	Day	35% 18% 33% 13% 1	270
March	1st to 10th	Day	24% 23% 34% 15% 3	420
	11th to 20th	Day	27% 17% 31% 19% 5% 1	420
	21st to end	Day	30% 19% 30% 15% 5% 1	462
April	1st to 10th	Day	27% 21% 29% 15% 6% 1	420
	11th to 20th	Day	32% 17% 24% 15% 8% 3	412
	21st to end	Day	29% 16% 33% 14% 5% 2	420
May	1st to 10th	Day	26% 15% 29% 20% 8% 3	423
	11th to 20th	Day	23% 15% 30% 20% 9% 3	447
	21st to end	Day	17% 16% 34% 20% 10% 2	485
June	1st to 10th	Day	23% 12% 36% 21% 7%	450
	11th to 20th	Day	19% 16% 27% 25% 11% 3	450
	21st to end	Day	16% 14% 33% 24% 10% 3	450
July	1st to 10th	Day	11% 8% 33% 35% 11% 2	445
	11th to 20th	Day	14% 11% 33% 26% 13% 3	444
	21st to end	Day	13% 10% 33% 29% 11% 3	488
August	1st to 10th	Day	16% 7% 34% 25% 13% 5%	446
	11th to 20th	Day	15% 6% 28% 27% 19% 6%	439
	21st to end	Day	17% 10% 31% 24% 12% 6%	495
September	1st to 10th	Day	16% 12% 30% 20% 14% 8%	450
	11th to 20th	Day	15% 11% 25% 24% 16% 8%	450
	21st to end	Day	19% 14% 26% 21% 15% 5%	450
October	1st to 10th	Day	25% 17% 23% 18% 14% 4	450
	11th to 20th	Day	29% 22% 27% 15% 6% 1	450
	21st to end	Day	34% 17% 25% 18% 5%	459
November	1st to 10th	Day	25% 18% 35% 15% 6% 1	266
	11th to 20th	Day	27% 24% 34% 7% 7% 1	180
	21st to end	Day	32% 22% 33% 9% 3 1	180
December	1st to 10th	Day	30% 16% 37% 13% 4	180
	11th to 20th	Day	31% 26% 31% 9% 2 1	180
	21st to end	Day	35% 17% 30% 13% 4 1	198
January	1st to 10th	Night	24% 18% 34% 19% 4	760
	11th to 20th	Night	26% 15% 31% 22% 6%	729
	21st to end	Night	17% 15% 35% 25% 7% 1	792
February	1st to 10th	Night	20% 20% 39% 16% 4	720
	11th to 20th	Night	21% 18% 39% 18% 4	703
	21st to end	Night	22% 20% 32% 23% 3	592
March	1st to 10th	Night	25% 18% 33% 21% 4	720
	11th to 20th	Night	23% 20% 32% 18% 6% 1	720
	21st to end	Night	21% 15% 34% 23% 8% 1	792
April	1st to 10th	Night	27% 16% 31% 22% 4	720
	11th to 20th	Night	26% 16% 31% 19% 8%	711
	21st to end	Night	24% 14% 27% 25% 9% 1	550
May	1st to 10th	Night	20% 11% 30% 29% 9% 1	388
	11th to 20th	Night	23% 10% 32% 26% 9% 1	354
	21st to end	Night	14% 11% 37% 27% 11%	389
June	1st to 10th	Night	18% 7% 38% 32% 5% 1	360
	11th to 20th	Night	18% 9% 29% 32% 11% 1	360
	21st to end	Night	19% 9% 29% 29% 13%	360
July	1st to 10th	Night	11% 7% 33% 36% 11% 2	350
	11th to 20th	Night	12% 8% 26% 38% 14% 1	348
	21st to end	Night	8% 6% 36% 35% 14% 1	394
August	1st to 10th	Night	12% 4 27% 34% 22% 1	487
	11th to 20th	Night	11% 3 23% 38% 21% 4	534
	21st to end	Night	14% 8% 30% 30% 17% 2	720
September	1st to 10th	Night	16% 6% 32% 27% 18% 2	720
	11th to 20th	Night	18% 7% 25% 29% 18% 3	720
	21st to end	Night	20% 10% 24% 25% 19% 2	720
October	1st to 10th	Night	26% 10% 28% 22% 13% 1	720
	11th to 20th	Night	26% 17% 28% 19% 8% 1	720
	21st to end	Night	29% 17% 28% 21% 5%	792
November	1st to 10th	Night	25% 16% 28% 22% 7% 1	740
	11th to 20th	Night	23% 21% 30% 16% 9% 1	760
	21st to end	Night	30% 18% 25% 23% 4	760
December	1st to 10th	Night	31% 18% 30% 16% 4	760
	11th to 20th	Night	26% 19% 29% 21% 4	760
	21st to end	Night	33% 16% 27% 19% 3 1	836

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