Lake St. Peter Provincial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lake St. Peter Provincial Park clear sky chart from 2005-11-06 to 2024-11-10.

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% 12% 4 9% 5% 5% 4 3 5% 6% 30%	101694
	Night	15% 13% 4 10% 5% 5% 4 3 5% 6% 30%	97408
Transparency	Day	54% 5% 10% 21% 10% 1	105253
	Night	54% 5% 10% 19% 10% 1	101937
Seeing	Day	24% 18% 31% 18% 7% 2	14454
	Night	22% 16% 30% 22% 8% 1	23598

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% 21% 6% 15% 6% 5% 3 3 4 4 20%	2517
	11th to 20th	Day	11% 16% 9% 21% 9% 6% 4 3 4 4 15%	2520
	21st to end	Day	17% 21% 10% 14% 5% 4 3 2 3 3 17%	3096
February	1st to 10th	Day	10% 18% 6% 15% 9% 5% 5% 3 4 5% 19%	1710
	11th to 20th	Day	11% 15% 6% 14% 7% 5% 5% 3 4 5% 25%	1663
	21st to end	Day	16% 16% 5% 10% 7% 6% 6% 3 5% 5% 22%	1475
March	1st to 10th	Day	16% 19% 5% 9% 5% 4 4 3 4 5% 25%	3330
	11th to 20th	Day	9% 18% 6% 13% 7% 5% 4 3 5% 5% 25%	3480
	21st to end	Day	12% 11% 4 9% 5% 4 4 3 4 5% 40%	3873
April	1st to 10th	Day	19% 14% 4 8% 6% 4 4 3 5% 6% 27%	2280
	11th to 20th	Day	22% 13% 3 6% 4 4 4 3 4 5% 34%	2278
	21st to end	Day	21% 12% 3 9% 4 3 3 2 4 5% 33%	2470
May	1st to 10th	Day	19% 9% 3 9% 5% 4 5% 3 5% 6% 32%	4324
	11th to 20th	Day	16% 10% 3 8% 5% 4 4 3 6% 8% 33%	4398
	21st to end	Day	16% 7% 3 6% 5% 5% 5% 4 5% 7% 39%	4837
June	1st to 10th	Day	21% 10% 3 6% 6% 5% 4 3 5% 7% 30%	2660
	11th to 20th	Day	15% 7% 2 7% 5% 5% 5% 5% 6% 9% 34%	2660
	21st to end	Day	17% 9% 3 6% 5% 5% 5% 5% 6% 8% 32%	2727
July	1st to 10th	Day	14% 7% 3 7% 5% 6% 5% 5% 7% 9% 33%	4440
	11th to 20th	Day	14% 5% 2 7% 5% 5% 5% 4 6% 8% 40%	4440
	21st to end	Day	10% 7% 3 6% 5% 5% 5% 4 6% 8% 43%	4814
August	1st to 10th	Day	16% 8% 3 8% 5% 6% 6% 4 6% 7% 31%	4109
	11th to 20th	Day	17% 7% 3 7% 5% 5% 6% 5% 7% 7% 32%	4044
	21st to end	Day	10% 6% 2 6% 5% 5% 6% 5% 6% 9% 39%	4290
September	1st to 10th	Day	16% 8% 2 6% 4 4 5% 4 5% 8% 38%	2280
	11th to 20th	Day	14% 8% 2 5% 4 4 3 4 5% 7% 44%	2271
	21st to end	Day	18% 9% 3 6% 4 5% 4 4 6% 7% 34%	1989
October	1st to 10th	Day	19% 11% 3 8% 4 4 4 3 5% 6% 33%	1900
	11th to 20th	Day	23% 15% 4 9% 5% 4 4 3 4 5% 23%	1900
	21st to end	Day	26% 15% 5% 9% 5% 4 4 3 4 5% 20%	2045
November	1st to 10th	Day	16% 14% 4 8% 5% 5% 3 4 5% 6% 30%	1636
	11th to 20th	Day	15% 18% 6% 11% 6% 4 3 4 5% 6% 22%	1520
	21st to end	Day	20% 21% 6% 11% 6% 4 4 3 3 6% 15%	1520
December	1st to 10th	Day	18% 24% 7% 12% 6% 4 4 2 4 4 14%	1520
	11th to 20th	Day	16% 20% 8% 13% 5% 4 4 3 4 4 19%	1906
	21st to end	Day	22% 23% 8% 15% 5% 2 1 1 3 4 16%	2772
January	1st to 10th	Night	16% 18% 7% 15% 7% 6% 5% 3 4 5% 14%	4429
	11th to 20th	Night	10% 16% 6% 18% 11% 7% 6% 4 5% 5% 13%	4440
	21st to end	Night	16% 17% 8% 15% 6% 7% 5% 3 4 5% 15%	4560
February	1st to 10th	Night	11% 17% 6% 13% 8% 6% 6% 4 4 5% 19%	2470
	11th to 20th	Night	12% 15% 6% 12% 5% 5% 6% 3 4 5% 26%	2403
	21st to end	Night	11% 17% 5% 10% 7% 6% 4 4 5% 6% 25%	1979
March	1st to 10th	Night	16% 15% 5% 10% 5% 5% 4 2 3 5% 29%	3508
	11th to 20th	Night	11% 19% 6% 10% 5% 4 4 4 5% 6% 26%	3479
	21st to end	Night	11% 11% 4 9% 6% 4 5% 4 6% 6% 34%	3758
April	1st to 10th	Night	19% 13% 4 8% 5% 4 4 3 5% 5% 30%	1900
	11th to 20th	Night	18% 11% 3 6% 5% 3 3 3 5% 5% 37%	1868
	21st to end	Night	18% 11% 4 8% 5% 5% 5% 3 4 5% 31%	1710
May	1st to 10th	Night	18% 9% 2 7% 4 4 4 4 5% 6% 37%	2615
	11th to 20th	Night	17% 9% 3 7% 4 3 4 3 6% 8% 36%	2495
	21st to end	Night	12% 7% 2 6% 5% 4 4 3 4 8% 42%	2738
June	1st to 10th	Night	16% 8% 2 7% 5% 4 5% 4 6% 9% 35%	1520
	11th to 20th	Night	12% 6% 3 6% 4 4 4 5% 6% 7% 43%	1520
	21st to end	Night	16% 7% 3 7% 5% 4 5% 4 5% 7% 36%	1396
July	1st to 10th	Night	10% 8% 2 8% 6% 4 6% 4 5% 7% 39%	2520
	11th to 20th	Night	14% 7% 2 6% 4 4 4 4 5% 7% 43%	2520
	21st to end	Night	10% 6% 2 6% 4 4 5% 3 6% 8% 48%	2739
August	1st to 10th	Night	11% 5% 2 6% 4 3 5% 4 6% 8% 46%	2817
	11th to 20th	Night	14% 8% 2 6% 4 4 4 3 5% 7% 42%	2785
	21st to end	Night	13% 5% 2 5% 4 4 4 4 6% 9% 45%	3334
September	1st to 10th	Night	11% 5% 2 6% 4 3 5% 4 6% 8% 47%	1900
	11th to 20th	Night	13% 6% 2 6% 4 3 4 3 5% 6% 48%	1908
	21st to end	Night	17% 8% 3 6% 4 3 4 4 4 5% 41%	2190
October	1st to 10th	Night	19% 10% 3 5% 4 4 3 3 5% 6% 38%	2280
	11th to 20th	Night	19% 14% 3 9% 5% 4 4 3 5% 6% 28%	2280
	21st to end	Night	23% 15% 4 8% 5% 5% 4 3 5% 5% 23%	2551
November	1st to 10th	Night	16% 14% 5% 8% 5% 5% 4 3 5% 6% 30%	2644
	11th to 20th	Night	17% 14% 5% 9% 6% 6% 5% 5% 5% 5% 25%	2660
	21st to end	Night	18% 17% 6% 11% 6% 6% 5% 3 4 6% 18%	2660
December	1st to 10th	Night	18% 21% 7% 12% 7% 6% 4 3 4 5% 13%	2660
	11th to 20th	Night	15% 21% 7% 13% 6% 4 3 3 4 4 20%	3288
	21st to end	Night	24% 21% 8% 14% 6% 4 3 2 3 4 12%	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	69% 5% 10% 9% 7%	2518
	11th to 20th	Day	75% 3 6% 9% 6% 1	2520
	21st to end	Day	74% 3 5% 10% 6% 2	3096
February	1st to 10th	Day	68% 5% 6% 14% 5% 1	1710
	11th to 20th	Day	62% 4 9% 13% 10% 2	1672
	21st to end	Day	64% 3 8% 13% 11% 1	1475
March	1st to 10th	Day	60% 5% 11% 11% 11% 1	3333
	11th to 20th	Day	60% 5% 10% 15% 8% 1	3480
	21st to end	Day	46% 5% 7% 22% 16% 4	3873
April	1st to 10th	Day	59% 4 6% 18% 10% 2	2280
	11th to 20th	Day	53% 4 6% 22% 13% 1	2278
	21st to end	Day	55% 4 6% 18% 13% 3	2470
May	1st to 10th	Day	51% 6% 7% 22% 11% 2	4337
	11th to 20th	Day	48% 8% 10% 24% 10% 1	4402
	21st to end	Day	44% 7% 12% 19% 15% 3	4837
June	1st to 10th	Day	54% 6% 9% 20% 11% 1	2660
	11th to 20th	Day	44% 7% 11% 23% 13% 2	2660
	21st to end	Day	48% 7% 11% 20% 12% 1	2727
July	1st to 10th	Day	46% 4 14% 25% 10% 1	4370
	11th to 20th	Day	41% 5% 14% 31% 10%	4365
	21st to end	Day	39% 5% 11% 32% 13%	4661
August	1st to 10th	Day	52% 4 12% 22% 9%	4095
	11th to 20th	Day	48% 5% 13% 26% 6% 1	4083
	21st to end	Day	40% 6% 11% 32% 10%	4290
September	1st to 10th	Day	42% 7% 12% 27% 12% 1	2280
	11th to 20th	Day	40% 6% 11% 29% 14% 1	2271
	21st to end	Day	49% 6% 11% 23% 10%	1989
October	1st to 10th	Day	51% 4 10% 27% 9% 1	3160
	11th to 20th	Day	55% 3 10% 20% 11% 1	3140
	21st to end	Day	63% 3 10% 17% 5%	3347
November	1st to 10th	Day	54% 6% 13% 19% 7% 1	1636
	11th to 20th	Day	63% 5% 11% 12% 7% 1	1520
	21st to end	Day	71% 6% 7% 10% 5% 1	1520
December	1st to 10th	Day	75% 4 6% 9% 5% 1	1520
	11th to 20th	Day	67% 7% 6% 10% 8% 1	1906
	21st to end	Day	76% 2 5% 13% 5%	2772
January	1st to 10th	Night	72% 6% 9% 10% 4	4429
	11th to 20th	Night	73% 7% 7% 8% 5% 1	4440
	21st to end	Night	72% 5% 7% 8% 7% 1	4560
February	1st to 10th	Night	66% 6% 9% 12% 7% 1	2470
	11th to 20th	Night	59% 5% 8% 18% 9% 1	2405
	21st to end	Night	59% 5% 7% 19% 9% 1	1979
March	1st to 10th	Night	59% 4 10% 15% 11% 1	3518
	11th to 20th	Night	58% 5% 12% 16% 7% 1	3480
	21st to end	Night	48% 6% 7% 22% 14% 2	3758
April	1st to 10th	Night	57% 4 8% 18% 12% 2	1900
	11th to 20th	Night	50% 4 7% 23% 15% 1	1868
	21st to end	Night	55% 5% 7% 17% 15% 2	1710
May	1st to 10th	Night	46% 7% 11% 23% 12% 2	2621
	11th to 20th	Night	44% 10% 11% 24% 10% 1	2496
	21st to end	Night	39% 6% 12% 25% 16% 2	2739
June	1st to 10th	Night	46% 6% 11% 22% 13% 1	1520
	11th to 20th	Night	38% 7% 11% 28% 15% 1	1520
	21st to end	Night	47% 6% 14% 20% 13% 1	1396
July	1st to 10th	Night	43% 5% 15% 21% 15% 1	2480
	11th to 20th	Night	41% 4 11% 32% 11%	2472
	21st to end	Night	35% 6% 13% 31% 15%	2651
August	1st to 10th	Night	37% 4 16% 27% 14% 2	2807
	11th to 20th	Night	41% 5% 17% 28% 9% 1	2812
	21st to end	Night	37% 5% 14% 32% 11% 2	3334
September	1st to 10th	Night	34% 8% 15% 29% 13% 1	1900
	11th to 20th	Night	36% 6% 13% 33% 12% 1	1908
	21st to end	Night	45% 6% 11% 27% 11%	2190
October	1st to 10th	Night	41% 3 10% 29% 16%	3800
	11th to 20th	Night	51% 3 13% 21% 12%	3779
	21st to end	Night	55% 4 17% 17% 6%	4199
November	1st to 10th	Night	54% 6% 11% 20% 8%	2644
	11th to 20th	Night	59% 7% 10% 16% 7% 1	2660
	21st to end	Night	67% 6% 9% 12% 5%	2660
December	1st to 10th	Night	73% 6% 7% 10% 4	2660
	11th to 20th	Night	67% 5% 6% 14% 7% 1	3288
	21st to end	Night	78% 3 4 9% 4	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	26% 24% 33% 13% 2 1	180
	11th to 20th	Day	32% 18% 33% 13% 3 1	180
	21st to end	Day	27% 20% 33% 16% 4	290
February	1st to 10th	Day	29% 29% 33% 7% 2	270
	11th to 20th	Day	26% 34% 33% 7%	270
	21st to end	Day	32% 25% 34% 7% 1	287
March	1st to 10th	Day	26% 22% 37% 13% 2	460
	11th to 20th	Day	28% 20% 34% 13% 4 1	460
	21st to end	Day	32% 22% 27% 13% 5% 1	506
April	1st to 10th	Day	28% 23% 31% 12% 5%	460
	11th to 20th	Day	38% 21% 21% 11% 7% 2	452
	21st to end	Day	31% 18% 32% 12% 5% 1	460
May	1st to 10th	Day	26% 18% 30% 17% 6% 3	463
	11th to 20th	Day	21% 18% 32% 20% 8% 2	487
	21st to end	Day	20% 19% 31% 20% 7% 2	529
June	1st to 10th	Day	25% 16% 34% 19% 6%	490
	11th to 20th	Day	17% 16% 33% 21% 10% 2	490
	21st to end	Day	21% 16% 33% 20% 8% 2	557
July	1st to 10th	Day	14% 10% 34% 31% 9% 2	485
	11th to 20th	Day	17% 12% 33% 23% 12% 3	484
	21st to end	Day	14% 12% 35% 26% 10% 2	532
August	1st to 10th	Day	16% 10% 35% 24% 12% 4	486
	11th to 20th	Day	16% 8% 27% 29% 15% 4	479
	21st to end	Day	17% 11% 31% 24% 12% 4	539
September	1st to 10th	Day	18% 13% 32% 20% 11% 6%	490
	11th to 20th	Day	17% 11% 25% 21% 17% 9%	490
	21st to end	Day	22% 15% 25% 21% 12% 5%	490
October	1st to 10th	Day	24% 20% 25% 17% 11% 3	490
	11th to 20th	Day	29% 24% 28% 14% 4 1	490
	21st to end	Day	36% 20% 28% 13% 3	514
November	1st to 10th	Day	29% 20% 29% 16% 5% 1	276
	11th to 20th	Day	32% 21% 31% 12% 4	180
	21st to end	Day	33% 24% 31% 9% 2 1	180
December	1st to 10th	Day	34% 19% 31% 13% 2	180
	11th to 20th	Day	36% 25% 27% 11% 1 1	180
	21st to end	Day	34% 26% 26% 10% 3 1	198
January	1st to 10th	Night	26% 21% 33% 15% 3 1	760
	11th to 20th	Night	27% 20% 32% 16% 5% 1	760
	21st to end	Night	19% 18% 34% 22% 6% 1	836
February	1st to 10th	Night	22% 23% 37% 17% 2	760
	11th to 20th	Night	20% 22% 41% 15% 3	743
	21st to end	Night	23% 25% 31% 18% 3	628
March	1st to 10th	Night	23% 24% 33% 17% 3	760
	11th to 20th	Night	21% 21% 35% 18% 4 1	760
	21st to end	Night	19% 19% 34% 21% 6%	836
April	1st to 10th	Night	27% 18% 31% 18% 5%	760
	11th to 20th	Night	26% 21% 26% 19% 8%	744
	21st to end	Night	24% 15% 28% 22% 10% 1	570
May	1st to 10th	Night	22% 11% 27% 29% 10% 1	442
	11th to 20th	Night	20% 11% 34% 29% 7%	374
	21st to end	Night	15% 12% 33% 29% 11%	411
June	1st to 10th	Night	18% 9% 36% 29% 7% 1	380
	11th to 20th	Night	17% 9% 28% 34% 12%	380
	21st to end	Night	20% 11% 27% 30% 12%	380
July	1st to 10th	Night	9% 8% 33% 34% 16% 1	370
	11th to 20th	Night	14% 7% 30% 33% 15% 1	368
	21st to end	Night	10% 6% 34% 38% 12% 1	416
August	1st to 10th	Night	12% 6% 24% 36% 21% 1	559
	11th to 20th	Night	11% 6% 22% 37% 22% 2	564
	21st to end	Night	14% 8% 28% 31% 17% 2	746
September	1st to 10th	Night	15% 8% 29% 29% 17% 1	760
	11th to 20th	Night	18% 8% 23% 27% 19% 4	760
	21st to end	Night	22% 11% 22% 27% 16% 2	760
October	1st to 10th	Night	25% 14% 28% 21% 11% 2	760
	11th to 20th	Night	26% 17% 30% 19% 7% 1	760
	21st to end	Night	33% 17% 26% 20% 4	836
November	1st to 10th	Night	28% 16% 28% 22% 5%	779
	11th to 20th	Night	25% 21% 32% 14% 8% 1	760
	21st to end	Night	31% 18% 28% 18% 4 1	760
December	1st to 10th	Night	30% 20% 33% 13% 4	760
	11th to 20th	Night	26% 22% 33% 15% 3 1	760
	21st to end	Night	33% 19% 31% 14% 3	836

Page generated at 2024-11-07 06:55:49. Version ac07

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