Fort Providence
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fort Providence clear sky chart from 2005-11-06 to 2026-01-02.

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	8% 9% 3 9% 6% 6% 6% 5% 6% 8% 34%	131845
	Night	7% 12% 5% 11% 7% 6% 6% 5% 7% 8% 28%	128125
Transparency	Day	46% 7% 16% 23% 8% 1	131492
	Night	52% 7% 14% 20% 7%	128058
Seeing	Day	13% 7% 24% 31% 19% 6%	18806
	Night	13% 5% 22% 34% 21% 4	26536

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	4 12% 5% 16% 10% 10% 11% 6% 6% 8% 12%	1803
	11th to 20th	Day	3 10% 4 12% 7% 5% 8% 7% 5% 9% 28%	2468
	21st to end	Day	5% 15% 6% 14% 8% 6% 7% 6% 7% 8% 18%	2992
February	1st to 10th	Day	4 8% 4 12% 8% 7% 6% 7% 8% 9% 28%	1385
	11th to 20th	Day	5% 12% 6% 12% 8% 6% 5% 5% 7% 8% 26%	1560
	21st to end	Day	3 12% 6% 13% 7% 8% 7% 6% 8% 7% 24%	1386
March	1st to 10th	Day	3 11% 5% 15% 9% 7% 7% 5% 7% 8% 24%	4518
	11th to 20th	Day	6% 12% 5% 15% 9% 9% 6% 5% 6% 7% 22%	4643
	21st to end	Day	3 9% 4 11% 6% 6% 6% 5% 6% 7% 38%	5969
April	1st to 10th	Day	7% 12% 4 10% 7% 5% 5% 3 5% 6% 37%	2475
	11th to 20th	Day	5% 9% 3 8% 6% 5% 5% 5% 5% 7% 43%	2723
	21st to end	Day	6% 11% 4 10% 7% 6% 6% 5% 7% 7% 31%	2885
May	1st to 10th	Day	5% 6% 2 7% 5% 6% 5% 5% 6% 8% 46%	7010
	11th to 20th	Day	9% 9% 4 8% 5% 5% 5% 5% 7% 8% 35%	7283
	21st to end	Day	8% 8% 3 7% 5% 5% 5% 4 7% 8% 39%	8470
June	1st to 10th	Day	12% 8% 3 8% 6% 5% 6% 5% 7% 9% 33%	3600
	11th to 20th	Day	10% 7% 3 8% 6% 6% 7% 5% 7% 9% 33%	3600
	21st to end	Day	9% 6% 3 6% 5% 6% 5% 5% 7% 10% 38%	3600
July	1st to 10th	Day	9% 6% 2 7% 6% 5% 6% 5% 8% 11% 35%	8160
	11th to 20th	Day	11% 6% 2 6% 4 4 4 4 6% 7% 45%	7972
	21st to end	Day	6% 4 2 6% 5% 5% 5% 5% 7% 9% 46%	7877
August	1st to 10th	Day	8% 5% 2 6% 5% 5% 5% 4 5% 6% 50%	5184
	11th to 20th	Day	16% 6% 2 6% 4 4 4 3 5% 7% 43%	4547
	21st to end	Day	13% 8% 3 8% 5% 6% 5% 5% 6% 8% 32%	4970
September	1st to 10th	Day	15% 8% 3 7% 5% 5% 4 4 7% 8% 34%	2510
	11th to 20th	Day	14% 10% 2 7% 4 4 6% 4 6% 8% 35%	2356
	21st to end	Day	14% 10% 4 8% 5% 5% 5% 5% 6% 8% 30%	2190
October	1st to 10th	Day	7% 11% 4 10% 5% 5% 6% 5% 6% 7% 33%	3162
	11th to 20th	Day	12% 13% 5% 12% 6% 5% 6% 4 5% 7% 24%	2932
	21st to end	Day	8% 15% 6% 11% 7% 6% 7% 5% 6% 6% 24%	2723
November	1st to 10th	Day	12% 17% 5% 13% 8% 6% 5% 4 5% 4 20%	1442
	11th to 20th	Day	9% 22% 7% 13% 6% 5% 6% 4 4 5% 19%	1249
	21st to end	Day	8% 17% 7% 12% 10% 9% 7% 4 4 5% 19%	1050
December	1st to 10th	Day	7% 16% 7% 15% 10% 9% 8% 4 7% 5% 13%	1588
	11th to 20th	Day	6% 14% 7% 16% 9% 8% 5% 3 8% 8% 17%	1539
	21st to end	Day	7% 18% 6% 14% 7% 7% 7% 4 6% 5% 18%	2024
January	1st to 10th	Night	5% 12% 7% 16% 10% 11% 8% 5% 6% 6% 14%	8165
	11th to 20th	Night	4 9% 5% 11% 6% 6% 8% 6% 7% 9% 27%	7429
	21st to end	Night	5% 14% 5% 12% 7% 6% 8% 5% 7% 7% 23%	7964
February	1st to 10th	Night	4 8% 5% 13% 8% 6% 6% 6% 7% 9% 27%	3033
	11th to 20th	Night	5% 13% 6% 12% 8% 6% 6% 5% 6% 7% 27%	2726
	21st to end	Night	4 14% 5% 13% 8% 8% 6% 5% 7% 7% 24%	2243
March	1st to 10th	Night	2 10% 5% 12% 7% 6% 6% 5% 9% 8% 29%	5376
	11th to 20th	Night	3 10% 4 13% 9% 8% 7% 5% 7% 8% 27%	5356
	21st to end	Night	2 6% 4 9% 5% 5% 5% 4 7% 8% 44%	5006
April	1st to 10th	Night	7% 14% 4 10% 7% 5% 6% 4 5% 7% 33%	1924
	11th to 20th	Night	5% 9% 4 7% 6% 5% 5% 5% 7% 7% 41%	1624
	21st to end	Night	7% 10% 4 8% 8% 6% 6% 5% 6% 7% 33%	1515
May	1st to 10th	Night	5% 5% 3 7% 5% 5% 5% 4 7% 9% 46%	2936
	11th to 20th	Night	8% 7% 4 8% 6% 6% 7% 5% 7% 10% 31%	2611
	21st to end	Night	9% 7% 3 9% 5% 6% 5% 5% 7% 9% 35%	2402
June	1st to 10th	Night	10% 7% 3 9% 6% 6% 6% 5% 7% 7% 35%	800
	11th to 20th	Night	8% 7% 4 8% 5% 5% 5% 5% 9% 7% 38%	800
	21st to end	Night	8% 5% 3 8% 5% 6% 6% 7% 6% 9% 40%	800
July	1st to 10th	Night	6% 4 2 8% 6% 6% 7% 6% 10% 10% 34%	1800
	11th to 20th	Night	8% 6% 3 6% 5% 5% 5% 5% 7% 9% 41%	1972
	21st to end	Night	5% 3 2 5% 4 5% 6% 4 7% 9% 50%	2966
August	1st to 10th	Night	7% 5% 2 5% 4 3 4 4 6% 8% 52%	1952
	11th to 20th	Night	11% 7% 2 6% 3 5% 5% 3 6% 7% 44%	2499
	21st to end	Night	11% 8% 3 9% 5% 5% 5% 5% 6% 8% 36%	2930
September	1st to 10th	Night	14% 7% 2 7% 5% 4 4 4 6% 10% 37%	1890
	11th to 20th	Night	12% 11% 2 8% 5% 4 4 4 6% 9% 34%	2044
	21st to end	Night	12% 10% 3 9% 6% 5% 5% 4 6% 8% 31%	2210
October	1st to 10th	Night	8% 13% 3 8% 5% 6% 6% 4 6% 8% 33%	4034
	11th to 20th	Night	9% 14% 5% 12% 5% 5% 4 3 5% 6% 33%	4216
	21st to end	Night	9% 18% 6% 12% 6% 6% 6% 4 6% 6% 20%	5034
November	1st to 10th	Night	13% 17% 6% 14% 8% 6% 5% 3 4 5% 20%	3075
	11th to 20th	Night	10% 18% 6% 14% 7% 5% 5% 4 6% 5% 20%	3367
	21st to end	Night	8% 16% 6% 14% 9% 7% 5% 5% 7% 6% 17%	3570
December	1st to 10th	Night	4 15% 8% 17% 9% 7% 7% 5% 6% 7% 14%	5809
	11th to 20th	Night	6% 16% 7% 14% 8% 6% 5% 5% 6% 7% 20%	6873
	21st to end	Night	6% 15% 5% 13% 7% 7% 8% 6% 7% 8% 17%	9174

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% 11% 13% 2	1803
	11th to 20th	Day	52% 7% 8% 20% 13%	2486
	21st to end	Day	61% 8% 12% 13% 6%	2992
February	1st to 10th	Day	48% 5% 14% 25% 7%	1385
	11th to 20th	Day	54% 8% 16% 18% 4	1568
	21st to end	Day	55% 7% 13% 19% 6%	1386
March	1st to 10th	Day	55% 6% 12% 20% 7%	4518
	11th to 20th	Day	60% 6% 11% 17% 6%	4643
	21st to end	Day	42% 7% 13% 26% 12%	5969
April	1st to 10th	Day	48% 5% 16% 22% 9%	2475
	11th to 20th	Day	40% 6% 14% 31% 9%	2723
	21st to end	Day	48% 8% 15% 21% 7%	2885
May	1st to 10th	Day	35% 5% 11% 30% 16% 2	7010
	11th to 20th	Day	42% 8% 14% 26% 9% 1	7287
	21st to end	Day	39% 7% 11% 25% 15% 3	8471
June	1st to 10th	Day	45% 8% 14% 26% 6% 1	3600
	11th to 20th	Day	43% 10% 15% 23% 8%	3600
	21st to end	Day	38% 9% 18% 26% 8% 1	3600
July	1st to 10th	Day	40% 9% 26% 18% 7%	8071
	11th to 20th	Day	36% 7% 15% 33% 9%	7873
	21st to end	Day	30% 9% 23% 37% 2	7656
August	1st to 10th	Day	33% 7% 17% 28% 14%	5165
	11th to 20th	Day	40% 8% 13% 21% 18%	4591
	21st to end	Day	49% 9% 21% 20% 1	4969
September	1st to 10th	Day	46% 10% 22% 20% 3	2510
	11th to 20th	Day	45% 9% 23% 21% 2	2356
	21st to end	Day	50% 10% 21% 16% 3	2190
October	1st to 10th	Day	48% 8% 18% 23% 3	3162
	11th to 20th	Day	59% 6% 17% 17% 1	2932
	21st to end	Day	60% 7% 17% 14% 2	2723
November	1st to 10th	Day	66% 7% 15% 9% 2	1442
	11th to 20th	Day	67% 7% 13% 10% 3	1249
	21st to end	Day	67% 6% 13% 10% 4	1050
December	1st to 10th	Day	71% 5% 9% 11% 4	1588
	11th to 20th	Day	64% 6% 10% 16% 4	1540
	21st to end	Day	66% 6% 13% 11% 3	2024
January	1st to 10th	Night	68% 6% 9% 13% 3	8165
	11th to 20th	Night	51% 6% 10% 20% 13% 1	7473
	21st to end	Night	55% 9% 14% 15% 6%	7964
February	1st to 10th	Night	50% 8% 12% 23% 8%	3033
	11th to 20th	Night	55% 7% 14% 20% 5%	2728
	21st to end	Night	57% 7% 12% 19% 6%	2243
March	1st to 10th	Night	47% 8% 14% 24% 7%	5376
	11th to 20th	Night	52% 8% 9% 21% 10%	5357
	21st to end	Night	35% 6% 12% 27% 19% 1	5006
April	1st to 10th	Night	49% 7% 13% 21% 10% 1	1924
	11th to 20th	Night	38% 6% 13% 28% 14% 1	1624
	21st to end	Night	47% 7% 13% 24% 9%	1515
May	1st to 10th	Night	32% 6% 14% 28% 17% 2	2936
	11th to 20th	Night	43% 8% 13% 23% 12%	2611
	21st to end	Night	43% 7% 8% 23% 17% 1	2402
June	1st to 10th	Night	44% 9% 12% 28% 7%	800
	11th to 20th	Night	39% 8% 15% 26% 10% 1	800
	21st to end	Night	36% 9% 19% 29% 7%	800
July	1st to 10th	Night	38% 10% 26% 20% 6%	1780
	11th to 20th	Night	37% 8% 15% 31% 8%	1948
	21st to end	Night	27% 8% 22% 42% 2	2882
August	1st to 10th	Night	30% 7% 22% 29% 13%	1946
	11th to 20th	Night	37% 9% 15% 18% 20%	2521
	21st to end	Night	45% 9% 22% 23% 2	2930
September	1st to 10th	Night	41% 9% 22% 23% 4	1890
	11th to 20th	Night	45% 8% 21% 21% 4	2044
	21st to end	Night	49% 9% 19% 20% 3 1	2210
October	1st to 10th	Night	46% 8% 18% 23% 4	4034
	11th to 20th	Night	53% 5% 15% 24% 3	4216
	21st to end	Night	62% 7% 15% 15% 1	5034
November	1st to 10th	Night	67% 6% 13% 11% 3	3075
	11th to 20th	Night	64% 8% 13% 12% 3	3367
	21st to end	Night	65% 7% 13% 12% 3	3570
December	1st to 10th	Night	68% 6% 11% 13% 2	5809
	11th to 20th	Night	62% 6% 10% 17% 4	6871
	21st to end	Night	61% 7% 15% 13% 3	9174

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	9% 7% 22% 33% 23% 6%	202
	11th to 20th	Day	16% 6% 20% 30% 20% 10%	200
	21st to end	Day	13% 3 29% 33% 18% 4	220
February	1st to 10th	Day	6% 6% 32% 30% 20% 7%	200
	11th to 20th	Day	4 7% 32% 33% 21% 6%	200
	21st to end	Day	4 7% 30% 31% 21% 7%	225
March	1st to 10th	Day	5% 8% 22% 30% 23% 11%	500
	11th to 20th	Day	11% 8% 28% 29% 18% 5%	500
	21st to end	Day	9% 8% 31% 32% 16% 5%	550
April	1st to 10th	Day	14% 9% 27% 30% 15% 4	500
	11th to 20th	Day	10% 9% 22% 31% 21% 7%	492
	21st to end	Day	15% 9% 27% 29% 16% 4	585
May	1st to 10th	Day	13% 12% 27% 30% 16% 3	803
	11th to 20th	Day	13% 10% 26% 30% 16% 5%	922
	21st to end	Day	13% 8% 25% 33% 17% 4	1006
June	1st to 10th	Day	17% 8% 25% 28% 18% 5%	930
	11th to 20th	Day	12% 6% 22% 33% 20% 6%	930
	21st to end	Day	11% 5% 21% 33% 22% 8%	930
July	1st to 10th	Day	14% 5% 19% 32% 24% 6%	916
	11th to 20th	Day	11% 5% 17% 34% 27% 7%	912
	21st to end	Day	10% 4 15% 33% 28% 9%	1013
August	1st to 10th	Day	11% 5% 15% 32% 27% 10%	924
	11th to 20th	Day	17% 8% 24% 31% 16% 5%	570
	21st to end	Day	17% 6% 20% 31% 18% 8%	583
September	1st to 10th	Day	20% 9% 25% 24% 17% 5%	530
	11th to 20th	Day	15% 7% 27% 26% 18% 7%	530
	21st to end	Day	14% 10% 33% 26% 14% 3	530
October	1st to 10th	Day	19% 12% 28% 23% 14% 5%	464
	11th to 20th	Day	21% 6% 28% 29% 15% 2	330
	21st to end	Day	16% 10% 30% 28% 12% 4	267
November	1st to 10th	Day	14% 5% 35% 25% 15% 8%	220
	11th to 20th	Day	17% 5% 25% 35% 11% 7%	220
	21st to end	Day	15% 5% 22% 38% 13% 7%	220
December	1st to 10th	Day	13% 8% 24% 32% 20% 4	220
	11th to 20th	Day	11% 4 22% 33% 24% 5%	220
	21st to end	Day	10% 4 15% 36% 26% 9%	242
January	1st to 10th	Night	13% 4 23% 33% 22% 6%	1107
	11th to 20th	Night	13% 4 22% 36% 20% 4	1100
	21st to end	Night	14% 6% 24% 35% 18% 3	1210
February	1st to 10th	Night	6% 5% 24% 37% 22% 6%	961
	11th to 20th	Night	10% 5% 24% 36% 23% 2	784
	21st to end	Night	10% 4 22% 38% 24% 3	660
March	1st to 10th	Night	6% 4 24% 35% 25% 7%	800
	11th to 20th	Night	10% 6% 26% 34% 23% 2	800
	21st to end	Night	8% 3 25% 38% 23% 4	880
April	1st to 10th	Night	11% 7% 29% 31% 19% 3	724
	11th to 20th	Night	8% 7% 27% 37% 19% 1	436
	21st to end	Night	12% 7% 29% 32% 18% 2	400
May	1st to 10th	Night	10% 6% 31% 36% 17% 1	400
	11th to 20th	Night	12% 7% 24% 35% 20% 2	394
	21st to end	Night	12% 6% 23% 36% 21% 1	433
June	1st to 10th	Night	13% 5% 20% 36% 23% 3	400
	11th to 20th	Night	9% 4 19% 38% 27% 4	400
	21st to end	Night	11% 2 17% 35% 31% 4	400
July	1st to 10th	Night	12% 3 19% 34% 28% 4	390
	11th to 20th	Night	9% 3 17% 38% 30% 3	388
	21st to end	Night	8% 1 13% 38% 35% 5%	438
August	1st to 10th	Night	9% 4 14% 35% 28% 10%	398
	11th to 20th	Night	13% 4 20% 33% 27% 3	396
	21st to end	Night	15% 3 19% 32% 27% 5%	462
September	1st to 10th	Night	18% 6% 23% 29% 20% 4	690
	11th to 20th	Night	18% 5% 20% 36% 16% 5%	800
	21st to end	Night	16% 8% 25% 34% 16% 2	800
October	1st to 10th	Night	16% 7% 23% 34% 17% 3	800
	11th to 20th	Night	20% 5% 25% 31% 17% 2	800
	21st to end	Night	22% 6% 23% 27% 17% 4	975
November	1st to 10th	Night	20% 6% 22% 30% 18% 4	1025
	11th to 20th	Night	18% 5% 20% 34% 18% 4	1129
	21st to end	Night	15% 5% 21% 33% 21% 6%	1160
December	1st to 10th	Night	12% 4 22% 40% 19% 3	1160
	11th to 20th	Night	14% 4 21% 37% 22% 3	1160
	21st to end	Night	13% 3 17% 32% 28% 6%	1276

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