Spruce Woods Provincial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Spruce Woods Provincial Park clear sky chart from 2005-11-06 to 2024-11-04.

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	11% 9% 3 8% 5% 5% 5% 4 6% 8% 36%	105537
	Night	9% 10% 4 9% 6% 5% 5% 4 6% 7% 37%	102074
Transparency	Day	45% 7% 15% 25% 8%	105289
	Night	45% 7% 14% 24% 9% 1	101968
Seeing	Day	15% 9% 31% 28% 14% 3	16232
	Night	14% 7% 32% 34% 12% 1	26151

By Month

Percentage Cloud Cover NW (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	5% 18% 6% 14% 7% 5% 5% 5% 7% 7% 19%	2219
	11th to 20th	Day	3 9% 6% 16% 10% 11% 11% 5% 7% 8% 14%	2371
	21st to end	Day	9% 13% 5% 13% 6% 6% 6% 4 6% 6% 27%	2794
February	1st to 10th	Day	10% 12% 5% 12% 8% 7% 7% 5% 8% 7% 20%	1537
	11th to 20th	Day	6% 10% 5% 10% 10% 7% 7% 6% 7% 8% 25%	1679
	21st to end	Day	6% 12% 4 12% 9% 6% 6% 5% 6% 6% 27%	1570
March	1st to 10th	Day	10% 12% 4 10% 8% 6% 6% 5% 7% 9% 23%	3130
	11th to 20th	Day	7% 14% 6% 11% 8% 6% 5% 4 7% 7% 24%	3436
	21st to end	Day	9% 10% 6% 14% 7% 5% 5% 3 6% 7% 28%	3872
April	1st to 10th	Day	9% 11% 4 8% 5% 4 5% 4 6% 8% 36%	2304
	11th to 20th	Day	13% 11% 4 10% 6% 4 5% 4 5% 6% 30%	2442
	21st to end	Day	15% 9% 3 8% 5% 5% 5% 4 6% 6% 34%	2470
May	1st to 10th	Day	21% 10% 3 7% 4 4 4 3 6% 7% 33%	4200
	11th to 20th	Day	20% 9% 3 8% 5% 5% 4 4 6% 6% 31%	4659
	21st to end	Day	19% 7% 2 7% 4 4 5% 4 6% 8% 35%	5173
June	1st to 10th	Day	14% 7% 2 6% 5% 5% 5% 5% 7% 8% 36%	2850
	11th to 20th	Day	15% 6% 3 6% 6% 5% 5% 4 7% 7% 35%	2850
	21st to end	Day	12% 6% 2 6% 5% 4 6% 5% 7% 10% 37%	2850
July	1st to 10th	Day	9% 4 1 5% 4 5% 6% 5% 9% 10% 42%	4750
	11th to 20th	Day	7% 4 2 5% 4 4 5% 4 7% 9% 48%	4750
	21st to end	Day	5% 3 2 5% 4 4 5% 4 8% 10% 50%	4875
August	1st to 10th	Day	9% 5% 3 6% 4 4 5% 4 7% 9% 45%	4412
	11th to 20th	Day	10% 5% 2 4 3 4 4 4 6% 9% 47%	4041
	21st to end	Day	10% 6% 2 6% 4 3 4 3 5% 9% 48%	4532
September	1st to 10th	Day	11% 5% 2 6% 3 4 4 3 5% 7% 51%	2321
	11th to 20th	Day	14% 6% 2 7% 5% 3 3 3 5% 7% 44%	2090
	21st to end	Day	15% 6% 2 7% 3 3 3 3 6% 7% 45%	2090
October	1st to 10th	Day	13% 8% 2 6% 4 3 3 2 5% 6% 48%	3335
	11th to 20th	Day	9% 8% 2 7% 5% 4 4 3 5% 8% 44%	2925
	21st to end	Day	14% 12% 4 8% 3 4 4 4 5% 7% 35%	3091
November	1st to 10th	Day	18% 14% 5% 10% 5% 4 4 3 4 5% 29%	1641
	11th to 20th	Day	8% 16% 6% 12% 8% 4 3 3 4 6% 29%	1497
	21st to end	Day	10% 15% 5% 11% 8% 4 5% 4 4 5% 29%	1330
December	1st to 10th	Day	7% 14% 6% 16% 9% 7% 6% 5% 5% 7% 18%	1330
	11th to 20th	Day	10% 15% 8% 14% 8% 6% 5% 5% 6% 6% 18%	1679
	21st to end	Day	7% 11% 5% 11% 5% 5% 4 4 5% 7% 37%	2442
January	1st to 10th	Night	6% 15% 6% 14% 7% 7% 7% 4 6% 6% 21%	4737
	11th to 20th	Night	5% 11% 5% 15% 9% 8% 9% 6% 7% 7% 18%	4520
	21st to end	Night	8% 14% 7% 14% 7% 5% 5% 4 5% 6% 25%	4873
February	1st to 10th	Night	8% 12% 5% 12% 8% 6% 6% 6% 6% 6% 26%	2642
	11th to 20th	Night	7% 10% 4 9% 6% 6% 7% 5% 6% 7% 33%	2403
	21st to end	Night	7% 11% 4 9% 7% 6% 5% 4 6% 8% 32%	1884
March	1st to 10th	Night	9% 12% 4 11% 7% 5% 6% 4 7% 7% 29%	3734
	11th to 20th	Night	6% 13% 4 8% 5% 5% 4 3 6% 8% 38%	3522
	21st to end	Night	7% 11% 4 12% 7% 5% 5% 4 6% 7% 32%	3758
April	1st to 10th	Night	6% 7% 4 7% 6% 5% 4 5% 6% 8% 42%	1875
	11th to 20th	Night	14% 14% 3 7% 6% 4 4 3 5% 6% 33%	1689
	21st to end	Night	13% 9% 3 7% 5% 5% 5% 5% 5% 7% 37%	1710
May	1st to 10th	Night	21% 8% 2 6% 4 4 4 3 4 6% 36%	2767
	11th to 20th	Night	15% 8% 2 6% 4 4 5% 4 5% 7% 41%	2247
	21st to end	Night	18% 6% 3 5% 4 4 3 4 4 6% 42%	2414
June	1st to 10th	Night	11% 7% 2 5% 3 3 5% 5% 6% 9% 44%	1330
	11th to 20th	Night	12% 6% 2 5% 6% 4 4 4 6% 8% 43%	1330
	21st to end	Night	10% 5% 1 5% 4 5% 5% 4 8% 10% 43%	1330
July	1st to 10th	Night	10% 3 1 4 4 4 5% 5% 7% 10% 48%	2220
	11th to 20th	Night	6% 3 2 4 3 4 4 4 6% 8% 57%	2220
	21st to end	Night	4 4 1 4 4 5% 5% 5% 7% 8% 54%	2685
August	1st to 10th	Night	6% 4 2 6% 4 4 5% 4 6% 8% 51%	2528
	11th to 20th	Night	6% 4 2 5% 4 4 5% 4 6% 11% 50%	2798
	21st to end	Night	11% 5% 2 4 3 3 3 3 5% 7% 53%	3135
September	1st to 10th	Night	8% 5% 2 5% 4 3 4 4 6% 8% 53%	1856
	11th to 20th	Night	13% 5% 2 4 4 4 4 2 6% 8% 48%	2090
	21st to end	Night	15% 7% 2 6% 4 3 4 3 5% 7% 44%	2090
October	1st to 10th	Night	12% 8% 2 5% 4 4 3 3 4 7% 47%	3592
	11th to 20th	Night	10% 7% 2 6% 4 4 4 4 6% 8% 44%	3998
	21st to end	Night	7% 9% 3 7% 5% 4 5% 4 6% 6% 43%	4467
November	1st to 10th	Night	12% 12% 4 8% 6% 4 5% 4 6% 6% 32%	2508
	11th to 20th	Night	9% 15% 6% 12% 7% 4 4 3 5% 6% 28%	2679
	21st to end	Night	10% 13% 5% 11% 7% 5% 5% 3 4 6% 31%	2850
December	1st to 10th	Night	7% 12% 5% 14% 8% 7% 5% 5% 7% 6% 25%	2850
	11th to 20th	Night	9% 16% 6% 14% 7% 6% 5% 4 5% 6% 21%	3518
	21st to end	Night	7% 10% 4 11% 6% 5% 5% 4 5% 6% 36%	5225

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	61% 8% 14% 14% 3	2219
	11th to 20th	Day	64% 9% 9% 15% 3	2394
	21st to end	Day	55% 7% 10% 22% 6%	2794
February	1st to 10th	Day	60% 7% 11% 16% 6%	1537
	11th to 20th	Day	53% 9% 12% 18% 9%	1688
	21st to end	Day	55% 7% 13% 18% 7%	1570
March	1st to 10th	Day	54% 8% 16% 17% 6%	3130
	11th to 20th	Day	55% 9% 12% 19% 5%	3438
	21st to end	Day	54% 7% 10% 21% 8%	3872
April	1st to 10th	Day	45% 6% 13% 26% 9% 1	2304
	11th to 20th	Day	54% 5% 12% 18% 11% 1	2442
	21st to end	Day	48% 7% 15% 21% 8% 1	2470
May	1st to 10th	Day	49% 6% 13% 22% 9% 1	4200
	11th to 20th	Day	51% 7% 10% 22% 9% 1	4663
	21st to end	Day	45% 9% 11% 25% 8% 1	5173
June	1st to 10th	Day	42% 8% 17% 21% 10% 1	2850
	11th to 20th	Day	46% 8% 15% 20% 10% 1	2850
	21st to end	Day	40% 10% 19% 24% 6% 1	2850
July	1st to 10th	Day	32% 11% 27% 24% 5%	4676
	11th to 20th	Day	30% 7% 20% 35% 7%	4669
	21st to end	Day	27% 7% 24% 32% 9%	4721
August	1st to 10th	Day	35% 7% 18% 29% 10%	4396
	11th to 20th	Day	32% 7% 20% 34% 7%	4080
	21st to end	Day	34% 5% 21% 31% 8%	4531
September	1st to 10th	Day	33% 5% 16% 33% 11% 2	2321
	11th to 20th	Day	40% 7% 16% 26% 9% 1	2090
	21st to end	Day	40% 6% 15% 30% 10%	2090
October	1st to 10th	Day	38% 4 11% 38% 9%	3335
	11th to 20th	Day	39% 5% 12% 33% 11%	2925
	21st to end	Day	49% 5% 11% 26% 8%	3091
November	1st to 10th	Day	58% 4 12% 17% 7% 1	1641
	11th to 20th	Day	57% 5% 16% 16% 6%	1497
	21st to end	Day	56% 9% 14% 16% 5%	1330
December	1st to 10th	Day	64% 7% 13% 12% 4	1330
	11th to 20th	Day	64% 8% 11% 12% 4	1680
	21st to end	Day	46% 7% 12% 22% 12% 1	2442
January	1st to 10th	Night	59% 10% 10% 17% 5%	4737
	11th to 20th	Night	62% 7% 11% 15% 4	4558
	21st to end	Night	59% 8% 10% 19% 5%	4873
February	1st to 10th	Night	56% 6% 13% 17% 8%	2642
	11th to 20th	Night	47% 8% 14% 19% 11%	2404
	21st to end	Night	48% 6% 14% 22% 10%	1884
March	1st to 10th	Night	51% 7% 14% 22% 5%	3734
	11th to 20th	Night	41% 7% 17% 24% 11% 1	3522
	21st to end	Night	50% 6% 12% 25% 7%	3758
April	1st to 10th	Night	38% 7% 12% 25% 16% 2	1875
	11th to 20th	Night	52% 6% 10% 19% 12% 1	1689
	21st to end	Night	45% 6% 14% 20% 12% 2	1710
May	1st to 10th	Night	48% 6% 10% 24% 12%	2767
	11th to 20th	Night	42% 8% 12% 24% 10% 4	2247
	21st to end	Night	42% 6% 14% 27% 11%	2414
June	1st to 10th	Night	36% 7% 19% 25% 11% 2	1330
	11th to 20th	Night	39% 8% 15% 25% 11% 2	1330
	21st to end	Night	34% 9% 22% 27% 7% 1	1330
July	1st to 10th	Night	29% 9% 25% 28% 8% 1	2185
	11th to 20th	Night	23% 7% 18% 41% 10% 1	2178
	21st to end	Night	25% 6% 24% 33% 11% 1	2600
August	1st to 10th	Night	30% 6% 16% 32% 14% 2	2520
	11th to 20th	Night	28% 7% 21% 33% 10% 1	2825
	21st to end	Night	32% 6% 18% 34% 10% 1	3135
September	1st to 10th	Night	29% 6% 13% 34% 15% 2	1856
	11th to 20th	Night	35% 6% 18% 27% 13% 1	2090
	21st to end	Night	40% 6% 11% 31% 11% 1	2090
October	1st to 10th	Night	37% 4 13% 30% 15% 2	3592
	11th to 20th	Night	37% 4 12% 32% 13% 1	3998
	21st to end	Night	41% 5% 13% 34% 7%	4467
November	1st to 10th	Night	51% 7% 14% 18% 7% 2	2508
	11th to 20th	Night	56% 7% 14% 15% 6% 1	2679
	21st to end	Night	55% 7% 15% 17% 6%	2850
December	1st to 10th	Night	57% 7% 15% 15% 6%	2850
	11th to 20th	Night	63% 6% 14% 12% 4	3516
	21st to end	Night	47% 7% 14% 18% 12% 1	5225

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	11% 11% 31% 31% 13% 3	270
	11th to 20th	Day	9% 11% 37% 31% 11% 2	270
	21st to end	Day	15% 9% 31% 30% 12% 2	297
February	1st to 10th	Day	17% 7% 43% 24% 8% 1	270
	11th to 20th	Day	7% 12% 40% 30% 10% 1	270
	21st to end	Day	7% 9% 40% 29% 13% 1	225
March	1st to 10th	Day	17% 12% 29% 29% 9% 3	270
	11th to 20th	Day	12% 13% 30% 29% 14% 2	270
	21st to end	Day	17% 8% 35% 24% 14% 2	330
April	1st to 10th	Day	16% 15% 33% 27% 7% 2	484
	11th to 20th	Day	18% 12% 34% 22% 12% 1	640
	21st to end	Day	17% 11% 31% 27% 12% 1	650
May	1st to 10th	Day	19% 10% 30% 27% 14% 2	653
	11th to 20th	Day	18% 10% 32% 23% 14% 3	675
	21st to end	Day	20% 11% 23% 27% 16% 3	734
June	1st to 10th	Day	16% 11% 29% 25% 14% 5%	680
	11th to 20th	Day	17% 10% 33% 24% 13% 3	680
	21st to end	Day	12% 8% 27% 31% 18% 4	680
July	1st to 10th	Day	10% 4 28% 29% 21% 8%	671
	11th to 20th	Day	10% 7% 30% 28% 19% 5%	668
	21st to end	Day	6% 5% 27% 35% 21% 7%	739
August	1st to 10th	Day	9% 6% 25% 32% 22% 7%	676
	11th to 20th	Day	12% 6% 22% 28% 23% 9%	665
	21st to end	Day	13% 8% 25% 32% 18% 4	748
September	1st to 10th	Day	12% 8% 34% 29% 14% 4	531
	11th to 20th	Day	18% 7% 30% 32% 11% 3	300
	21st to end	Day	21% 10% 31% 26% 11% 1	300
October	1st to 10th	Day	26% 13% 25% 23% 11% 3	300
	11th to 20th	Day	16% 11% 34% 28% 8% 2	300
	21st to end	Day	23% 8% 37% 22% 7% 2	330
November	1st to 10th	Day	30% 8% 30% 23% 9% 1	279
	11th to 20th	Day	15% 14% 33% 30% 9%	270
	21st to end	Day	17% 11% 39% 28% 4 1	270
December	1st to 10th	Day	17% 7% 35% 27% 11% 3	270
	11th to 20th	Day	14% 13% 41% 27% 4 1	270
	21st to end	Day	12% 5% 37% 33% 10% 3	297
January	1st to 10th	Night	12% 9% 37% 31% 10% 1	950
	11th to 20th	Night	15% 7% 39% 31% 8% 1	950
	21st to end	Night	15% 8% 35% 34% 8% 1	1045
February	1st to 10th	Night	13% 7% 36% 31% 11% 1	950
	11th to 20th	Night	11% 7% 34% 36% 10% 2	929
	21st to end	Night	12% 5% 34% 36% 11% 2	628
March	1st to 10th	Night	15% 7% 30% 34% 12% 2	760
	11th to 20th	Night	10% 9% 36% 31% 13% 2	599
	21st to end	Night	15% 7% 30% 33% 13% 2	627
April	1st to 10th	Night	10% 7% 35% 37% 10% 1	570
	11th to 20th	Night	20% 7% 31% 32% 10% 1	563
	21st to end	Night	16% 6% 33% 34% 10% 1	570
May	1st to 10th	Night	18% 6% 27% 37% 10% 1	570
	11th to 20th	Night	17% 8% 27% 35% 13%	561
	21st to end	Night	21% 8% 27% 33% 12%	617
June	1st to 10th	Night	14% 6% 34% 31% 14% 2	570
	11th to 20th	Night	13% 6% 32% 36% 14% 1	570
	21st to end	Night	11% 6% 24% 39% 18% 1	570
July	1st to 10th	Night	8% 3 25% 41% 22% 2	555
	11th to 20th	Night	7% 5% 27% 41% 18% 1	552
	21st to end	Night	7% 3 23% 46% 19% 3	624
August	1st to 10th	Night	8% 3 24% 44% 21% 1	567
	11th to 20th	Night	8% 4 23% 38% 25% 3	564
	21st to end	Night	12% 6% 24% 41% 16% 2	627
September	1st to 10th	Night	10% 4 29% 37% 18% 2	570
	11th to 20th	Night	14% 8% 28% 41% 9%	570
	21st to end	Night	17% 8% 29% 33% 11% 1	570
October	1st to 10th	Night	18% 8% 34% 30% 10%	630
	11th to 20th	Night	19% 8% 30% 32% 10%	890
	21st to end	Night	16% 11% 35% 28% 8% 1	1045
November	1st to 10th	Night	17% 8% 38% 28% 8% 1	943
	11th to 20th	Night	16% 8% 37% 28% 9% 2	950
	21st to end	Night	16% 12% 37% 27% 7% 1	950
December	1st to 10th	Night	11% 9% 35% 33% 10% 2	950
	11th to 20th	Night	17% 9% 35% 28% 8% 2	950
	21st to end	Night	18% 5% 33% 31% 11% 2	1045

Page generated at 2024-11-01 21:47:41. Version ac07

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